iOS-related warnings when packaging for Android

When packaging a game for Android, we see a bunch of warnings like this:

> Plugin 'Packages/com.cesium.unity/Plugins/iOS/lib/libCesiumGeospatial.a' doesn't have CPU architecture set, since it's a native plugin, valid architecture is required, skipping.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)
> Plugin 'Packages/com.cesium.unity/Plugins/iOS/lib/libCesiumUtility.a' doesn't have CPU architecture set, since it's a native plugin, valid architecture is required, skipping.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)
> Plugin 'Packages/com.cesium.unity/Plugins/iOS/lib/libsqlite3.a' doesn't have CPU architecture set, since it's a native plugin, valid architecture is required, skipping.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

We should see if we can tweak the .meta file settings so that the Android build doesn't think it should be pulling in these iOS files.

Inspect the .meta settings for the native libraries under Packages/com.cesium.unity/Plugins/iOS/lib, starting with the Android packaging path that reports these warnings. Verify the import settings exclude the iOS plugins from Android builds, then package for Android and confirm the warnings no longer appear.

Written by the indexing model from the issue text.