Update SlicePermissionActivity component in manifest

After ag/15315839, all explicit intents has to match the component's
intent filter declared in the manifest xml if the target package is
targeting T+. An incomplete intent filter has been set for
SlicePermissionActivity, which causes all slice permission request
intents fail to resolve and deliver to SystemUI.

Because SliceProvider.SLICE_TYPE is not a valid MIME type that can be
used for intent filters, the least complicated solution is to remove the
intent filter altogether and check the intent in the activity code.

Bug: 207782463
Test: atest SlicePermissionsTest#testPermissionIntent
Change-Id: I47b1e5d860976bbcd446ae3d21fab0e988279c5e