MM-9728: Online migration for advanced permissions phase 2 (#8744)

* MM-9728: Online migration for advanced permissions phase 2

* Add unit tests for new store functions.

* Move migration specific code to own file.

* Add migration state function test.

* Style fixes.

* Add i18n strings.

* Fix mocks.

* Add TestMain to migrations package tests.

* Fix typo.

* Fix review comments.

* Fix up the "Check if migration is done" check to actually work.

i18n/en.json

@@ -47,6 +47,54 @@
     "id": "September",
     "translation": "September"
   },
+  {
+    "id": "migrations.worker.run_advanced_permissions_phase_2_migration.invalid_progress",
+    "translation": "Migration failed due to invalid progress data."
+  },
+  {
+    "id": "migrations.worker.run_migration.unknown_key",
+    "translation": "Cannot run migration job due to unknown migration key."
+  },
+  {
+    "id": "store.sql_channel.migrate_channel_members.open_transaction.app_error",
+    "translation": "Failed to open the database transaction"
+  },
+  {
+    "id": "store.sql_channel.migrate_channel_members.select.app_error",
+    "translation": "Failed to select the batch of channel members"
+  },
+  {
+    "id": "store.sql_channel.migrate_channel_members.rollback_transaction.app_error",
+    "translation": "Failed to roll back the database transaction"
+  },
+  {
+    "id": "store.sql_channel.migrate_channel_members.update.app_error",
+    "translation": "Failed to update the channel member"
+  },
+  {
+    "id": "store.sql_channel.migrate_channel_members.commit_transaction.app_error",
+    "translation": "Failed to commit the database transaction"
+  },
+  {
+    "id": "store.sql_team.migrate_team_members.open_transaction.app_error",
+    "translation": "Failed to open the database transaction"
+  },
+  {
+    "id": "store.sql_team.migrate_team_members.select.app_error",
+    "translation": " Failed to select the batch of team members"
+  },
+  {
+    "id": "store.sql_team.migrate_team_members.rollback_transaction.app_error",
+    "translation": "Failed to roll back the database transaction"
+  },
+  {
+    "id": "store.sql_team.migrate_team_members.update.app_error",
+    "translation": "Failed to update the team member"
+  },
+  {
+    "id": "store.sql_team.migrate_team_members.commit_transaction.app_error",
+    "translation": "Failed to commit the database transaction"
+  },
   {
     "id": "api.admin.add_certificate.no_file.app_error",
     "translation": "No file under 'certificate' in request."