[lib] Prevent SET_AUX_USER_FIDS from overwriting state when no changes

Summary:
I was seeing a React render cycle after introducing D13443. When I updated `useUpdateRelationships` to depend on `auxUserInfos`, it caused the hook to get generated when `auxUserInfos` changed. This caused the effect in `FarcasterDataHandler` to run again, which resulted in `auxUserInfos` changing again.

To break this loop, this diff makes sure we only change `auxUserInfos` if there are actual changes.

Depends on D13443

Test Plan: Confirm that the React render cycle no longer prevents me from logging in as the `commeth` account

Reviewers: will, varun

Reviewed By: will

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13453

lib/reducers/aux-user-reducer.js

@@ -39,22 +39,27 @@ function reduceAuxUserStore(
     const replaceOperations: ReplaceAuxUserInfoOperation[] = [];
     for (const userID in state.auxUserInfos) {
       if (
-        state.auxUserInfos[userID].fid !== null &&
-        !toUpdateUserIDs.has(userID)
+        state.auxUserInfos[userID].fid === null ||
+        toUpdateUserIDs.has(userID)
       ) {
-        replaceOperations.push({
-          type: 'replace_aux_user_info',
-          payload: {
-            id: userID,
-            auxUserInfo: {
-              ...state.auxUserInfos[userID],
-              fid: null,
-            },
-          },
-        });
+        continue;
       }
+      replaceOperations.push({
+        type: 'replace_aux_user_info',
+        payload: {
+          id: userID,
+          auxUserInfo: {
+            ...state.auxUserInfos[userID],
+            fid: null,
+          },
+        },
+      });
     }
     for (const farcasterUser of action.payload.farcasterUsers) {
+      const existingAuxUserInfo = state.auxUserInfos[farcasterUser.userID];
+      if (existingAuxUserInfo?.fid === farcasterUser.farcasterID) {
+        continue;
+      }
       replaceOperations.push({
         type: 'replace_aux_user_info',
         payload: {