Allow ephemeral apps to reach any CATEGORY_BROWSABLE

Apps receiving browsable intents should already be prompting the user
before taking any action/making any changes, which is what we want to
ensure for ephemeral apps. This way we don't have to manually mark all
such activities visibleToInstantApps.

Test: cts-tradefed run commandAndExit cts-dev -m
CtsAppSecurityHostTestCases -t android.appsecurity.cts.EphemeralTest
Change-Id: Id64706f993a412f163e533fa85b83f5f466731f7