recovery: Delete internal verifyPackageCompatibility.

Non-A/B has been deprecated for long. During non-A/B updates,
compatibility.zip is checked with VintfObject.verify(), which
is another deprecated function that always returns compatible
if a list of package VINTF XMLs are supplied. (see below.) Hence, the private
RecoverySystem.verifyPackageCompatibility was just useless code
that unconditionally returns true except for invalid ZIP file.
Remove it. Replace the public RecoverySystem.verifyPackageCompatibility
and make it return true unconditonally.

VintfObject.verify() with OTA XMLs are deprecated per
http://b/139300422 [VINTF] Delete OTA vintf checking code
in http://r.android.com/1194233 ("Delete VINTF compatibility checks
during OTA."), in 2019. We had decided that compatibility checks
during OTA should be removed, and moved to OTA generation time instead.
Using an old libvintf on the device to check against new libvintf
metadata required forward compatibility of libvintf, which cannot be
achieved. Instead, the device should verify the signature of the OTA to
verify its source.

Test: TH
Bug: 270169217
Bug: 139300422
Change-Id: I775d29e4cd1d165233e07cfb820d1fe343fa4757