Apply min aspect ratio override only for portrait only activities

This only affects the min aspect ratio override, developers can still set min aspect ratio in the manifest regadless of whether the app is fixed to portrait. This change is needed since applying the override on activities that aren't fixed to portrait results in unintended behavior (see bug for more context).

Fix: 202842551
Test: atest WmTests:SizeCompatTests
Change-Id: Iebd8edf1fc43ee892aea78715c9b217950df5a3b