Progress towards splitting MediaProvider UID.

We're working towards making MediaProvider into a Mainline module,
which means it can no longer share the "android.media" UID built
into the OS.  The major reason for this is because they're signed
with separate keys, but a secondary reason is that we don't know what
database customizations an OEM has performed in their MediaProvider.

Ensure that packages are requesting the permissions they actually
depend on, instead of relying on permissions requested by other
packages under the shared UID.

Bug: 144247087
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: Iea42a69dd270682258314126f6540478aece3e59