Stop relying on AppOpsManager#checkPackage(), which is deprecated

With this CL,

  InputMethodUtils#checkIfPackageBelongsToUid()

starts using

  PackageManagerInternal#getPackageUid()

instead of

  AppOpsManager#checkPackage(),

which is deprecated [1].

There should be no semantic change in this CL.

 [1]: I90215a638a3c380fcffde2b9209c4386f8fd70ea
      a04b9ab4

Bug: 234882948
Test: presubmit
Change-Id: I069b058b4240fb7ab638915b03d433e32660870f