Fix: Retry builds were not being cancelled properly (#12615)

[SahiRB1104]

Summary

This PR fixes an issue where a build created as retry would not change
to cancelled when a cancel action was triggered on the original build.

Details

Retry builds inherit the previous build state, but were not part of the
state transition that sets a build to cancelled. This caused retry
builds to remain active even after cancellation.

This PR updates the cancel logic so that:

• both running and retried builds are included
• state is consistently set to cancelled
• state transition follows existing expected workflow

Testing

A regression test is added:

• test_cancel_build.py
  Covers:
• cancelling a running retry build
• cancelling a triggered retry build

Issue reference

Fixes #12615

[SahiRB1104]

I ran the new test_cancel_build tests locally.
Some unrelated tests fail on my Windows setup (path normalization / external dependencies), but the new tests pass. Please let me know if I should adjust anything.

[SahiRB1104]

This fixes an issue where old running builds weren’t always cancelled correctly when triggering a new build.

1. add update_state flag to cancel_build
2. always update DB + notification when user cancels
3. skip DB updates for automatic cancels (update_state=False)
4. update affected tests in test_trigger_build and test_core_utils
5. add dedicated tests for cancel_build behaviour

All CI checks passed.