[Autofill] : Fix save regression with relayout

TrackedViews are saved without session ids. However, when relayout is
enabled without relative position, session id was being attached to the
autofill ids. This can be problematic, as the autofill ids saved with
tracked views now contain session ids, but don't match the hashCode of
when they were put into the tracking set. As such, when those views
become invisible, the corresponding autofill id's aren't removed from
the visible set. As such, save isn't shown.

This fix removes setting the session id when enable_relayout is enabled.

Bug: 369882186
Test: atest android.autofillservice.cts.dropdown.AuthenticationTest#testDatasetAuthThenModifyAndSaveOnViewsInvisible
	  Run the following test with the following setup
	    adb shell device_config put autofill enable_relayout true;
		adb shell device_config put autofill enable_relative_location_for_relayout false;
      This test fails without this change, but passes with this change.
Flag: EXEMPT : DeviceConfig flags used: enable_relayout
Change-Id: Idd65578f6ce1bfe04e221c569a33b62d7a98b4b4