Issue:
Bug: Use SignatureKey as auth_type for VGS connector



We need to collect a 3rd key (vault_id) apart from `username` and `password` in case of VGS for SDK use case

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 -->
- Change VGS auth type from BodyKey to SignatureKey

### 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).
-->
Closes #9067 

## 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)?
-->

Request:

```
curl --location 'http://localhost:8080/v2/connector-accounts' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'x-merchant-id: cloth_seller_v2_WmQmWko8QabakxqCypsz' \
--header 'x-profile-id: pro_vnTuyThRZPNGRWjIHrIt' \
--header 'Authorization: admin-api-key=test_admin' \
--header 'api-key: test_admin' \
--data '{
    "connector_type": "vault_processor",
    "connector_name": "vgs",
    "connector_account_details": {
        "auth_type": "SignatureKey",
        "api_key": "[REDACTED]",
        "key1": "[REDACTED]",
        "api_secret": "[REDACTED]"
    },
    "frm_configs": null,
    "connector_webhook_details": {
        "merchant_secret": ""
    },
    "profile_id": "pro_vnTuyThRZPNGRWjIHrIt"
}'


Response:

```json
{
    "connector_type": "vault_processor",
    "connector_name": "vgs",
    "connector_label": "vgs_businesss",
    "id": "mca_VsS4aBqNwMcPptFn4ZPL",
    "profile_id": "pro_vnTuyThRZPNGRWjIHrIt",
    "connector_account_details": {
        "auth_type": "SignatureKey",
        "api_key": "US********************q4",
        "key1": "ca********************************07",
        "api_secret": "st*ff"
    },
    "payment_methods_enabled": null,
    "connector_webhook_details": {
        "merchant_secret": "",
        "additional_secret": null
    },
    "metadata": null,
    "disabled": false,
    "frm_configs": null,
    "applepay_verified_domains": null,
    "pm_auth_config": null,
    "status": "active",
    "additional_merchant_data": null,
    "connector_wallets_details": null,
    "feature_metadata": null
}
```
## 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:


Request:

```
curl --location 'http://localhost:8080/v2/connector-accounts' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'x-merchant-id: cloth_seller_v2_WmQmWko8QabakxqCypsz' \
--header 'x-profile-id: pro_vnTuyThRZPNGRWjIHrIt' \
--header 'Authorization: admin-api-key=test_admin' \
--header 'api-key: test_admin' \
--data '{
    "connector_type": "vault_processor",
    "connector_name": "vgs",
    "connector_account_details": {
        "auth_type": "SignatureKey",
        "api_key": "[REDACTED]",
        "key1": "[REDACTED]",
        "api_secret": "[REDACTED]"
    },
    "frm_configs": null,
    "connector_webhook_details": {
        "merchant_secret": ""
    },
    "profile_id": "pro_vnTuyThRZPNGRWjIHrIt"
}'


Response:

```json
{
    "connector_type": "vault_processor",
    "connector_name": "vgs",
    "connector_label": "vgs_businesss",
    "id": "mca_VsS4aBqNwMcPptFn4ZPL",
    "profile_id": "pro_vnTuyThRZPNGRWjIHrIt",
    "connector_account_details": {
        "auth_type": "SignatureKey",
        "api_key": "US********************q4",
        "key1": "ca********************************07",
        "api_secret": "st*ff"
    },
    "payment_methods_enabled": null,
    "connector_webhook_details": {
        "merchant_secret": "",
        "additional_secret": null
    },
    "metadata": null,
    "disabled": false,
    "frm_configs": null,
    "applepay_verified_domains": null,
    "pm_auth_config": null,
    "status": "active",
    "additional_merchant_data": null,
    "connector_wallets_details": null,
    "feature_metadata": null
}
```

Patch:
diff --git a/crates/hyperswitch_connectors/src/connectors/vgs/transformers.rs b/crates/hyperswitch_connectors/src/connectors/vgs/transformers.rs
index 4915e2da400..4f996c2ffbe 100644
--- a/crates/hyperswitch_connectors/src/connectors/vgs/transformers.rs
+++ b/crates/hyperswitch_connectors/src/connectors/vgs/transformers.rs
@@ -74,15 +74,22 @@ impl<F> TryFrom<&VaultRouterData<F>> for VgsInsertRequest {
 pub struct VgsAuthType {
     pub(super) username: Secret<String>,
     pub(super) password: Secret<String>,
+    // vault_id is used in sessions API
+    pub(super) _vault_id: Secret<String>,
 }
 
 impl TryFrom<&ConnectorAuthType> for VgsAuthType {
     type Error = error_stack::Report<errors::ConnectorError>;
     fn try_from(auth_type: &ConnectorAuthType) -> Result<Self, Self::Error> {
         match auth_type {
-            ConnectorAuthType::BodyKey { api_key, key1 } => Ok(Self {
+            ConnectorAuthType::SignatureKey {
+                api_key,
+                key1,
+                api_secret,
+            } => Ok(Self {
                 username: api_key.to_owned(),
                 password: key1.to_owned(),
+                _vault_id: api_secret.to_owned(),
             }),
             _ => Err(errors::ConnectorError::FailedToObtainAuthType.into()),
         }