Update ActivityEmbeddingUtils

- Provide base Intent in the two-pane Settings API.
  By returning an Intent with ComponentName, this makes it easier
  to embed the Intent into a SaferPendingIntent.
- Only support API for scv2 platform.
- Update BuildCompatUtils to support isAtLeastSV2 and isAtLeastT.

Bug: 227563999
Test: rebuild
Change-Id: Ib054c5c37e29d43662bcf9b0d86ecbee7c2b921d