Rudderstack: Update init logic to automatically use new url when new config is set (#115275)

update rudderstack init logic
to rely on existence of old or new sdk config option being set and only defer to feature toggle if both or neither is set

public/app/core/services/echo/init.ts

@@ -146,7 +146,19 @@ async function initRudderstackBackend() {
     return;
   }
 
-  const modulePromise = config.featureToggles.rudderstackUpgrade
+  // this will need to be updated when rudderstackSdkV3Url is added
+  // Desired logic: if only one of the sdk urls is provided, use respective code
+  // otherwise defer to the feature toggle.
+  const fakeConfigRudderstackSdkV3Url: string | undefined = undefined;
+
+  const hasOldSdkUrl = Boolean(config.rudderstackSdkUrl);
+  const hasNewSdkUrl = Boolean(fakeConfigRudderstackSdkV3Url);
+  const onlyOneConfigURLSet = hasOldSdkUrl !== hasNewSdkUrl;
+  const useNewRudderstack = onlyOneConfigURLSet ? hasNewSdkUrl : config.featureToggles.rudderstackUpgrade;
+
+  const configUrl = useNewRudderstack ? fakeConfigRudderstackSdkV3Url : config.rudderstackSdkUrl;
+
+  const modulePromise = useNewRudderstack
     ? import('./backends/analytics/RudderstackV3Backend')
     : import('./backends/analytics/RudderstackBackend');
 
@@ -157,7 +169,7 @@ async function initRudderstackBackend() {
       dataPlaneUrl: config.rudderstackDataPlaneUrl,
       user: contextSrv.user,
       sdkUrl: config.rudderstackSdkUrl,
-      configUrl: config.rudderstackConfigUrl,
+      configUrl: configUrl,
       integrationsUrl: config.rudderstackIntegrationsUrl,
       buildInfo: config.buildInfo,
     })