ci(selective): force Seer public API matrix on publish_status edits (#122950)

## Summary
When a PR only flips `publish_status` to `PUBLIC` (no handler rewrite),
selective testing often never imports
`tests/sentry/seer/endpoints/test_organization_agent_token.py`. Master
still runs the full Seer public-mutation matrix, which auto-discovers
every PUBLIC mutation and fails if the endpoint 404s behind a
feature/plan gate.

That gap greened the issue-views publish PRs and then broke Backend on
master (and blocked s4s2 checks).

## Change
If any changed non-test `.py` file declares `publish_status`, always
include:
`tests/sentry/seer/endpoints/test_organization_agent_token.py`

## Test plan
- [x] `test_compute_sentry_selected_tests.py` (62 passed)
- [ ] CI on this PR

## Context
- Incident: s4s2 deploy checks + master Backend red on agent-token
matrix for `OrganizationGroupSearchViewsEndpoint` POST
- Related: publish revert already landed; matrix behavior for flag-gated
PUBLIC endpoints may still get a separate fix

<!-- junior-request-attribution:start -->
Requested by **dan**.
<!-- junior-request-attribution:end -->

<!-- junior-session-footer:start -->
<!-- junior-conversation-id:slack%3ACUHS29QJ0%3A1787868927.299429 -->

--

[View Junior
Session](https://junior-prod.sentry.dev/conversations/slack%3ACUHS29QJ0%3A1787868927.299429)
[[Sentry]](https://sentry.sentry.io/explore/conversations/slack%3ACUHS29QJ0%3A1787868927.299429/?project=4510944073809921)

<!-- junior-session-footer:end -->

---------

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: Dan Fuller <dfuller@sentry.io>