Do not allow FGS starts from sync

When requestSync() is called by a TOP app, we put grant the sync adapter
app temp-allowlist of 10 minutes.

We need to keep this behavior, but we shouldn't allow FGS to be started
in this window.

Fix: 178233289
Test: atest CtsSyncManagerTestsCases
Test: atest cts/tests/app/src/android/app/cts/ActivityManagerFgsBgStartTest.java

BYPASS_INCLUSIVE_LANGUAGE_REASON=Existing public API.

Change-Id: I5d32206bf97cdbc3678fbb4c710642ee0620fd07