refactor: Remove unnecessary undefined check in RPC tracking

selectedRpcEndpoint cannot be undefined here because:
- Save button is disabled without rpcEndpoints
- trackRpcUpdateFromBanner only set for existing networks
- Existing networks always have valid RPC endpoints

Author: cryptodev-2s

ui/pages/settings/networks-tab/networks-form/networks-form.test.js

@@ -88,11 +88,7 @@ describe('NetworkForm Component', () => {
   });
 
   beforeEach(() => {
-    // Clear mock call history to ensure test isolation and accurate assertions
-    // Each test verifies these actions are called with specific arguments
-    updateNetwork.mockClear(); // Reset calls from network update tests
-    addNetwork.mockClear(); // Reset calls from network creation tests
-    setTokenNetworkFilter.mockClear(); // Reset calls from token filter tests
+    jest.clearAllMocks();
 
     nock('https://chainid.network:443', { encodedQueryParams: true })
       .get('/chains.json')

ui/pages/settings/networks-tab/networks-form/networks-form.tsx

@@ -316,18 +316,16 @@ export const NetworksForm = ({
           // Track RPC update from network connection banner
           if (trackRpcUpdateFromBanner) {
             const selectedRpcEndpoint =
-              networkPayload.rpcEndpoints?.[
+              networkPayload.rpcEndpoints[
                 networkPayload.defaultRpcEndpointIndex
               ];
             const chainIdAsDecimal = hexToNumber(chainIdHex);
-            const sanitizedRpcUrl =
-              selectedRpcEndpoint &&
-              isPublicEndpointUrl(
-                selectedRpcEndpoint.url,
-                infuraProjectId ?? '',
-              )
-                ? onlyKeepHost(selectedRpcEndpoint.url)
-                : 'custom';
+            const sanitizedRpcUrl = isPublicEndpointUrl(
+              selectedRpcEndpoint.url,
+              infuraProjectId ?? '',
+            )
+              ? onlyKeepHost(selectedRpcEndpoint.url)
+              : 'custom';
 
             trackEvent({
               category: MetaMetricsEventCategory.Network,