metrics: Track RPC migration path (from/to) in banner update event

Change from single rpc_endpoint_url to from_rpc_domain and to_rpc_domain
properties to track the complete migration path when users switch RPCs
from the network connection banner.

This enables analytics to identify:
- Which RPC endpoints are problematic (high from_rpc_domain counts)
- Which RPC endpoints users prefer (high to_rpc_domain counts)
- Common migration patterns (FROM → TO pairs)

Author: cryptodev-2s

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

@@ -482,6 +482,18 @@ describe('NetworkForm Component', () => {
       <MetaMetricsContext.Provider value={mockTrackEvent}>
         <NetworksForm
           {...propNetworkDisplay}
+          networkFormState={{
+            ...propNetworkDisplay.networkFormState,
+            rpcUrls: {
+              defaultRpcEndpointIndex: 0,
+              rpcEndpoints: [
+                {
+                  url: 'https://monad-mainnet.infura.io/v3/',
+                  type: 'custom',
+                },
+              ],
+            },
+          }}
           existingNetwork={{
             chainId: '0x64',
             name: 'Ethereum',
@@ -509,7 +521,8 @@ describe('NetworkForm Component', () => {
         event: 'Network Connection Banner RPC Updated',
         properties: {
           chain_id_caip: 'eip155:100',
-          rpc_endpoint_url: 'mainnet.infura.io',
+          from_rpc_domain: 'mainnet.infura.io',
+          to_rpc_domain: 'monad-mainnet.infura.io',
         },
       });
     });
@@ -627,7 +640,8 @@ describe('NetworkForm Component', () => {
         event: 'Network Connection Banner RPC Updated',
         properties: {
           chain_id_caip: 'eip155:100',
-          rpc_endpoint_url: 'custom',
+          from_rpc_domain: 'custom',
+          to_rpc_domain: 'custom',
         },
       });
     });

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

@@ -315,17 +315,21 @@ export const NetworksForm = ({
 
           // Track RPC update from network connection banner
           if (trackRpcUpdateFromBanner) {
-            const selectedRpcEndpoint =
+            const newRpcEndpoint =
               networkPayload.rpcEndpoints[
                 networkPayload.defaultRpcEndpointIndex
               ];
+            const oldRpcEndpoint =
+              existingNetwork.rpcEndpoints[
+                existingNetwork.defaultRpcEndpointIndex ?? 0
+              ];
+
             const chainIdAsDecimal = hexToNumber(chainIdHex);
-            const sanitizedRpcUrl = isPublicEndpointUrl(
-              selectedRpcEndpoint.url,
-              infuraProjectId ?? '',
-            )
-              ? onlyKeepHost(selectedRpcEndpoint.url)
-              : 'custom';
+
+            const sanitizeRpcUrl = (url: string) =>
+              isPublicEndpointUrl(url, infuraProjectId ?? '')
+                ? onlyKeepHost(url)
+                : 'custom';
 
             trackEvent({
               category: MetaMetricsEventCategory.Network,
@@ -334,7 +338,8 @@ export const NetworksForm = ({
               /* eslint-disable @typescript-eslint/naming-convention */
               properties: {
                 chain_id_caip: `eip155:${chainIdAsDecimal}`,
-                rpc_endpoint_url: sanitizedRpcUrl,
+                from_rpc_domain: sanitizeRpcUrl(oldRpcEndpoint.url),
+                to_rpc_domain: sanitizeRpcUrl(newRpcEndpoint.url),
               },
               /* eslint-enable @typescript-eslint/naming-convention */
             });