chore: remove unused oauthV2Enabled logger (#6465)

🔒 Scanned for secrets using gitleaks 8.28.0

# Description

We are removing the unused `oauthV2Enabled` logger.

## Linear Ticket


https://linear.app/rudderstack/issue/INT-4213/remove-unused-oauthv2enabled-variable-from-devops-and-operator

## Security

- [ ] The code changed/added as part of this pull request won't create
any security issues with how the software is being used.

Author: ItsSudip

router/transformer/transformer.go

@@ -662,7 +662,6 @@ func (trans *handle) doProxyRequest(ctx context.Context, proxyUrl string, proxyR
 	req.Header.Set("RdProxy-Timeout", strconv.FormatInt(trans.destinationTimeout.Milliseconds(), 10))
 	httpReqStTime := time.Now()
 	var resp *http.Response
-	trans.logger.Debugn("[router delivery]", logger.NewBoolField("oauthV2Enabled", true))
 	req = req.WithContext(cntx.CtxWithDestInfo(req.Context(), proxyReqParams.DestInfo))
 	req = req.WithContext(cntx.CtxWithSecret(req.Context(), proxyReqParams.ResponseData.Metadata[0].Secret))
 	resp, err = trans.proxyClientOAuthV2.Do(req)