Block APK rejoining shared UID by dropping sharedUserMaxSdkVersion

Not only should the APK not change its sharedUserId declaration, it
shall also not be allowed to rejoin shared UID.

Test: atest SharedUserMigrationTest#testAppInstall
Bug: 221088088
Change-Id: I4b5d76179d9ed17d333f46b4dc4d7d12b470d130
1 file changed