Session states refactor.

1. Moving Seal (back) to commit call as we no longer need it to be async.

2. Current states:
     Stream/Validate/Commit - for Streaming installation might be entered multiple times while waiting for DataLoader to finish.
     Install - renamed from Commit to avoid confusion with mCommitted.

3. Install still has to be a separate state to allow
setPermissionsResult.

Test: atest PackageManagerShellCommandTest
Bug: b/136132412 b/133435829
Change-Id: I6afcfeafabbf7e26906fcf5697c44c5617c9c1b5