Guard TIF vendor extension APIs by new permission

Guard TvInputManager#getAvailableExtensionInterfaceNames() and
TvInputManager#getExtensionInterface() by
android.Manifest.permission.TIS_EXTENSION_INTERFACE.

Bug: 215189795
Bug: 193052431
Test: run cts -m CtsTvTestCases -t
android.media.tv.cts.TvInputManagerTest

Change-Id: I43d4f063b0a602f00f7f71e8fe08fb09c7a763bf