[native] handle errors when running migration to new flow

Summary:
[ENG-10094](https://linear.app/comm/issue/ENG-10094/migration-to-v2-is-not-working-on-non-primary-device).

`getAuthMetadata` can throw and then `backupUploadInProgress` is set to true forever

Depends on D14215

Test Plan: simulate error and check if it thrown

Reviewers: bartek, tomek

Reviewed By: bartek, tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D14216

native/backup/backup-handler.js

@@ -104,10 +104,19 @@ function BackupHandler(): null {
     void (async () => {
       backupUploadInProgress.current = true;
 
-      const [isPrimaryDevice, { userID, deviceID }] = await Promise.all([
-        checkIfPrimaryDevice(),
-        getAuthMetadata(),
-      ]);
+      let isPrimaryDevice, userID, deviceID;
+      try {
+        const [isPrimaryDeviceResult, authMetadata] = await Promise.all([
+          checkIfPrimaryDevice(),
+          getAuthMetadata(),
+        ]);
+        isPrimaryDevice = isPrimaryDeviceResult;
+        userID = authMetadata.userID;
+        deviceID = authMetadata.deviceID;
+      } catch (e) {
+        backupUploadInProgress.current = false;
+        return;
+      }
 
       // CurrentIdentityUserState is required to check if migration to
       // new flow is needed.