Issue:
Bug: fix(opensearch): add "@timestamp" field for opensearch locally



Add the `@timestamp` field to OpenSearch locally while creating index-patterns, as it is present in Elasticsearch and is causing mismatched results while using the ` /search ` api on SBX 


Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [x] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Added the `@timestamp` field to OpenSearch locally while creating index-patterns, as it is present in Elasticsearch and is causing mismatched results while using the /search api on SBX

### 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
<!--
Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless it is an obvious bug or documentation fix
that will have little conversation).
-->
To prevent mismatched data while using `/search` api

## How did you test it?
<!--
Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
-->
- Hit the `/search` API
```bash
curl --location 'http://localhost:8080/analytics/v1/search' \
--header 'Accept: */*' \
--header 'Accept-Language: en-US,en;q=0.9' \
--header 'Connection: keep-alive' \
--header 'Content-Type: application/json' \
--header 'Origin: http://localhost:9000' \
--header 'Referer: http://localhost:9000/' \
--header 'Sec-Fetch-Dest: empty' \
--header 'Sec-Fetch-Mode: cors' \
--header 'Sec-Fetch-Site: same-site' \
--header 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36' \
--header 'api-key: hyperswitch' \
--header 'authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoiYjc2ZDVmZjMtNGI1ZS00OTMyLTk1ZDItNmE3MTEyZWZiNTNlIiwibWVyY2hhbnRfaWQiOiJtZXJjaGFudF8xNzIxODE1MjkwIiwicm9sZV9pZCI6Im9yZ19hZG1pbiIsImV4cCI6MTcyMzEwMDIwMCwib3JnX2lkIjoib3JnX3VFNk1LbExxalU5MWlGUEVGck1rIiwicHJvZmlsZV9pZCI6bnVsbH0._jkEBwHNVeJ_sstB4fqttU2mWVI4pPQbuOkqyovHRcE' \
--header 'sec-ch-ua: "Not/A)Brand";v="8", "Chromium";v="126", "Google Chrome";v="126"' \
--header 'sec-ch-ua-mobile: ?0' \
--header 'sec-ch-ua-platform: "macOS"' \
--data '{
    "query": "usd",
    "filters": {
        "status": [
            "success"
        ]
    },
    "timeRange": {
        "startTime": "2024-07-23T00:30:00Z",
        "endTime": "2024-08-08T18:45:00Z"
    }
}'
```
![image](https://github.com/user-attachments/assets/7d35078d-32dc-4791-83df-7c3214d207cd)


## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [ ] I addressed lints thrown by `cargo clippy`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible


Testing:

- Hit the `/search` API
```bash
curl --location 'http://localhost:8080/analytics/v1/search' \
--header 'Accept: */*' \
--header 'Accept-Language: en-US,en;q=0.9' \
--header 'Connection: keep-alive' \
--header 'Content-Type: application/json' \
--header 'Origin: http://localhost:9000' \
--header 'Referer: http://localhost:9000/' \
--header 'Sec-Fetch-Dest: empty' \
--header 'Sec-Fetch-Mode: cors' \
--header 'Sec-Fetch-Site: same-site' \
--header 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36' \
--header 'api-key: hyperswitch' \
--header 'authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoiYjc2ZDVmZjMtNGI1ZS00OTMyLTk1ZDItNmE3MTEyZWZiNTNlIiwibWVyY2hhbnRfaWQiOiJtZXJjaGFudF8xNzIxODE1MjkwIiwicm9sZV9pZCI6Im9yZ19hZG1pbiIsImV4cCI6MTcyMzEwMDIwMCwib3JnX2lkIjoib3JnX3VFNk1LbExxalU5MWlGUEVGck1rIiwicHJvZmlsZV9pZCI6bnVsbH0._jkEBwHNVeJ_sstB4fqttU2mWVI4pPQbuOkqyovHRcE' \
--header 'sec-ch-ua: "Not/A)Brand";v="8", "Chromium";v="126", "Google Chrome";v="126"' \
--header 'sec-ch-ua-mobile: ?0' \
--header 'sec-ch-ua-platform: "macOS"' \
--data '{
    "query": "usd",
    "filters": {
        "status": [
            "success"
        ]
    },
    "timeRange": {
        "startTime": "2024-07-23T00:30:00Z",
        "endTime": "2024-08-08T18:45:00Z"
    }
}'
```
![image](https://github.com/user-attachments/assets/7d35078d-32dc-4791-83df-7c3214d207cd)

Patch:
diff --git a/config/vector.yaml b/config/vector.yaml
index 1511e09a05c..17049677fe5 100644
--- a/config/vector.yaml
+++ b/config/vector.yaml
@@ -60,6 +60,7 @@ transforms:
       - plus_1_events
     source: |-
       .timestamp = from_unix_timestamp!(.created_at, unit: "seconds")
+      ."@timestamp" = from_unix_timestamp(.created_at, unit: "seconds") ?? now()
 
   sdk_transformed:
     type: throttle
diff --git a/crates/analytics/src/opensearch.rs b/crates/analytics/src/opensearch.rs
index 11ea4e4f7ab..e74622a054a 100644
--- a/crates/analytics/src/opensearch.rs
+++ b/crates/analytics/src/opensearch.rs
@@ -493,7 +493,7 @@ impl OpenSearchQueryBuilder {
             let range = json!(time_range);
             filter_array.push(json!({
                 "range": {
-                    "timestamp": range
+                    "@timestamp": range
                 }
             }));
         }