Issue:
Bug: refactor(success_based): add support for exploration





Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This pull request introduces a new feature to support an "exploration percentage" parameter in success-based routing configurations and adds a "RoutingApproach" enum to define routing strategies. These changes span multiple files, including API specifications, Rust models, and protocol buffer definitions, ensuring end-to-end support for the new functionality.

### New Feature: Exploration Percentage in Routing Configurations
* Added `exploration_percent` parameter to the `SuccessBasedRoutingConfig` struct in Rust models (`crates/api_models/src/routing.rs`) and updated its default implementation. [[1]](diffhunk://#diff-6eb6e93a94555e904f304999acc96ab6125769971da9ec3dcbb30d5912b4fc45R963) [[2]](diffhunk://#diff-6eb6e93a94555e904f304999acc96ab6125769971da9ec3dcbb30d5912b4fc45R992)
* Modified the `update` method in `SuccessBasedRoutingConfigBody` to handle updates to the `exploration_percent` field.
* Updated the gRPC client (`crates/external_services/src/grpc_client/dynamic_routing/success_rate_client.rs`) to include the `exploration_percent` field in the `CalSuccessRateConfig` mapping.
* Enhanced the protocol buffer definition (`proto/success_rate.proto`) to include `exploration_percent` as an optional field in the `CalSuccessRateConfig` message.

### New Enum: Routing Approach
* Introduced a `RoutingApproach` enum with values `EXPLORATION` and `EXPLOITATION` in the protocol buffer definition (`proto/success_rate.proto`) and added it to the `CalSuccessRateResponse` message.
* Updated the OpenAPI specification (`api-reference/hyperswitch_intelligent_router_open_api_spec.yml`) to include the `RoutingApproach` type and its usage in API responses.

### API Specification Enhancements
* Added `exploration_percent` to the API's routing configuration schema in the OpenAPI spec.

### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
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## How did you test it?
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Did you write an integration/unit/API test to verify the code changes?
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1. Toggle success based routing for a profile, Check the business profile table in DB, get the routing_algorithm_id active for that profile and check in routing_algorithm table. it should have exploration set to 20.0

```
curl --location --request POST 'http://localhost:8080/account/merchant_1747851996/business_profile/pro_Rbh3PEV8EITILLoKDC6N/dynamic_routing/success_based/toggle?enable=dynamic_connector_selection' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: xyz' \
--data ''
```

## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible


Testing:

1. Toggle success based routing for a profile, Check the business profile table in DB, get the routing_algorithm_id active for that profile and check in routing_algorithm table. it should have exploration set to 20.0

```
curl --location --request POST 'http://localhost:8080/account/merchant_1747851996/business_profile/pro_Rbh3PEV8EITILLoKDC6N/dynamic_routing/success_based/toggle?enable=dynamic_connector_selection' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: xyz' \
--data ''
```

Patch:
diff --git a/api-reference-v2/openapi_spec.json b/api-reference-v2/openapi_spec.json
index 039981f661b..fbabc864672 100644
--- a/api-reference-v2/openapi_spec.json
+++ b/api-reference-v2/openapi_spec.json
@@ -23374,9 +23374,13 @@
           },
           "specificity_level": {
             "$ref": "#/components/schemas/SuccessRateSpecificityLevel"
+          },
+          "exploration_percent": {
+            "type": "number",
+            "format": "double",
+            "nullable": true
           }
-        },
-        "additionalProperties": false
+        }
       },
       "SuccessRateSpecificityLevel": {
         "type": "string",
diff --git a/crates/api_models/src/open_router.rs b/crates/api_models/src/open_router.rs
index f15d9cbcfeb..cfcb45ef97b 100644
--- a/crates/api_models/src/open_router.rs
+++ b/crates/api_models/src/open_router.rs
@@ -62,6 +62,7 @@ pub struct PaymentInfo {
 pub struct DecidedGateway {
     pub gateway_priority_map: Option<HashMap<String, f64>>,
     pub debit_routing_output: Option<DebitRoutingOutput>,
+    pub routing_approach: String,
 }
 
 #[derive(Debug, Serialize, Deserialize, PartialEq)]
diff --git a/crates/api_models/src/routing.rs b/crates/api_models/src/routing.rs
index a15b135ac1f..7633f44156e 100644
--- a/crates/api_models/src/routing.rs
+++ b/crates/api_models/src/routing.rs
@@ -960,6 +960,7 @@ impl Default for SuccessBasedRoutingConfig {
                     max_total_count: Some(5),
                 }),
                 specificity_level: SuccessRateSpecificityLevel::default(),
+                exploration_percent: Some(20.0),
             }),
             decision_engine_configs: None,
         }
@@ -980,7 +981,6 @@ pub enum DynamicRoutingConfigParams {
 }
 
 #[derive(serde::Serialize, serde::Deserialize, Debug, Clone, ToSchema)]
-#[serde(deny_unknown_fields)]
 pub struct SuccessBasedRoutingConfigBody {
     pub min_aggregates_size: Option<u32>,
     pub default_success_rate: Option<f64>,
@@ -988,6 +988,7 @@ pub struct SuccessBasedRoutingConfigBody {
     pub current_block_threshold: Option<CurrentBlockThreshold>,
     #[serde(default)]
     pub specificity_level: SuccessRateSpecificityLevel,
+    pub exploration_percent: Option<f64>,
 }
 
 #[derive(serde::Serialize, serde::Deserialize, Debug, Clone, ToSchema)]
@@ -1113,7 +1114,10 @@ impl SuccessBasedRoutingConfigBody {
                 .as_mut()
                 .map(|threshold| threshold.update(current_block_threshold));
         }
-        self.specificity_level = new.specificity_level
+        self.specificity_level = new.specificity_level;
+        if let Some(exploration_percent) = new.exploration_percent {
+            self.exploration_percent = Some(exploration_percent);
+        }
     }
 }
 
diff --git a/crates/external_services/src/grpc_client/dynamic_routing/success_rate_client.rs b/crates/external_services/src/grpc_client/dynamic_routing/success_rate_client.rs
index 278a2b50d15..b63f435327e 100644
--- a/crates/external_services/src/grpc_client/dynamic_routing/success_rate_client.rs
+++ b/crates/external_services/src/grpc_client/dynamic_routing/success_rate_client.rs
@@ -290,6 +290,7 @@ impl ForeignTryFrom<SuccessBasedRoutingConfigBody> for CalSuccessRateConfig {
                 SuccessRateSpecificityLevel::Merchant => Some(ProtoSpecificityLevel::Entity.into()),
                 SuccessRateSpecificityLevel::Global => Some(ProtoSpecificityLevel::Global.into()),
             },
+            exploration_percent: config.exploration_percent,
         })
     }
 }
diff --git a/crates/router/src/core/payments/routing.rs b/crates/router/src/core/payments/routing.rs
index b4ac7d4421d..86925cff09f 100644
--- a/crates/router/src/core/payments/routing.rs
+++ b/crates/router/src/core/payments/routing.rs
@@ -1776,10 +1776,7 @@ pub async fn perform_decide_gateway_call_with_open_router(
                 ))?;
 
             if let Some(gateway_priority_map) = decided_gateway.gateway_priority_map {
-                logger::debug!(
-                    "open_router decide_gateway call response: {:?}",
-                    gateway_priority_map
-                );
+                logger::debug!(gateway_priority_map=?gateway_priority_map, routing_approach=decided_gateway.routing_approach, "open_router decide_gateway call response");
                 routable_connectors.sort_by(|connector_choice_a, connector_choice_b| {
                     let connector_choice_a_score = gateway_priority_map
                         .get(&connector_choice_a.to_string())
diff --git a/proto/success_rate.proto b/proto/success_rate.proto
index 17d566af356..efdd439cac9 100644
--- a/proto/success_rate.proto
+++ b/proto/success_rate.proto
@@ -23,6 +23,7 @@ message CalSuccessRateConfig {
     uint32 min_aggregates_size = 1;
     double default_success_rate = 2;
     optional SuccessRateSpecificityLevel specificity_level = 3;
+    optional double exploration_percent = 4;
 }
 
 enum SuccessRateSpecificityLevel {
@@ -32,6 +33,12 @@ enum SuccessRateSpecificityLevel {
 
 message CalSuccessRateResponse {
     repeated LabelWithScore labels_with_score = 1;
+    RoutingApproach routing_approach = 2;
+}
+
+enum RoutingApproach {
+    EXPLORATION = 0;
+    EXPLOITATION = 1;
 }
 
 message LabelWithScore {