MABM: cleanup and tying up loose ends

[mna]

Backend

• [x] Assignee: Martin - Finish wiring up the migration of the existing ABM token (https://github.com/fleetdm/fleet/pull/21307#issue-2466128483), with tests (could not be done as part of the DB migration as too many things would've broken before the rest of the changes are implemented)
• [x] ~~Look into supporting multiple unit tests per database migration: https://github.com/fleetdm/fleet/pull/21287#discussion_r1715869345. Currently the mechanism for migration tests only supports 1 test (the migration is applied once, from only one starting state, and sometimes -as in our case- it is useful to test various starting states).~~
• [x] Assignee: Martin - Once the CRUD Datastore methods are merged in the feature branch for VPP tokens, update the VPP token migration worker to update the token row, and finalize tests.
• [ ] Once the ABM code has been fully updated to allow for multiple tokens, update/refactor the integration tests
• [ ] Assignee: Jahziel - Ensure we have a single set of constants for "No team" and "All teams" and we're using that in all places where those strings are used.
• [x] Assignee: Martin - Adjust fleet serve to ingest ABM flags into the new table
• [x] Assignee: Sarah - update the error response for POST /vpp_tokensto provide the information needed to support this UI. . the current error response is this { "message": "vpp token for team noteam already exists", "errors": [ { "name": "base", "reason": "vpp token for team noteam already exists" } ] }
• [x] Assignee: Dante #21550
• [x] Assignee: Martin - Ensure the macos_setup_assistant worker job is updated to handle multi ABM tokens (might need to receive the ABM token to use as part of the job? see https://github.com/fleetdm/fleet/pull/21592/files#diff-1092299ba8d3b798f70a35a3117d4318b263678f08f51ed3c50e3a476fd462bc)
• [x] Correct revisions to VPP/ABM endpoints

Frontend

• [x] Follow up on this comment regarding banner priorities
• [x] Update links in banners to use new frontend routes
• [x] Fix VPP/ABM tables to sort by org name
• [ ] integrations with API and ensuring correct messages (NOTE: done but will need another final pass when all BE work is completed)
• [x] premium message when free tier on abm and vpp pages