Fix bug where existing icon is removed when install session is abandonded.

- Ensure we only add promise icons for apps that aren't already installed to
  our internal list of session ids.
- Ensure we only remove promise icons created from the install session when
  that session is abandonded.

Bug: 140819614
Change-Id: I3c93865b5e96a9c7a160154b45a38eb90ac9d183