ITEP-91742: Ensure scene updates always emit DB topic notifications

[Copilot]

📝 Description

Scene update notifications on the DB topic were dropped for update paths with no validated field deltas, causing downstream consumers to miss scene refresh events. This change restores a guaranteed post-commit notification path for those cases.

• What changed
  • Model: added Scene.notifydbupdate() to enqueue sendUpdateCommand(scene_id=self.pk) on transaction commit.
  • Serializer: in SceneSerializer.create_update, when is_update and validated_data is effectively empty, call instance.notifydbupdate() instead of silently returning.
• Why it matters
  • Preserves event semantics: scene update intent now emits a DB update message even when no persisted fields change (e.g., metadata-only/update-trigger flows).

if is_update:
  for key, value in validated_data.items():
    setattr(instance, key, value)
  instance.save(send_update_command=send_update_command)
else:
  instance.notifydbupdate()

JIRA: ITEP-91742

✨ Type of Change

Select the type of change your PR introduces:

• 🐞 Bug fix – Non-breaking change which fixes an issue
• 🚀 New feature – Non-breaking change which adds functionality
• 🔨 Refactor – Non-breaking change which refactors the code base
• 💥 Breaking change – Changes that break existing functionality
• 📚 Documentation update
• 🔒 Security update
• 🧪 Tests
• 🚂 CI

🧪 Testing Scenarios

Describe how the changes were tested and how reviewers can test them too:

• ✅ Tested manually
• 🤖 Ran automated end-to-end tests

✅ Checklist

Before submitting the PR, ensure the following:

• 🔍 PR title is clear and descriptive
• 📝 For internal contributors: If applicable, include the JIRA ticket number (e.g., ITEP-123456) in the PR title. Do not include full URLs
• 💬 I have commented my code, especially in hard-to-understand areas
• 📄 I have made corresponding changes to the documentation
• ✅ I have added tests that prove my fix is effective or my feature works

[saratpoluri]

@sbelhaik : this test: https://jira.devtools.intel.com/secure/Tests.jspa#/testCase/NEX-T12750
Doesn't explicit cover verifying that the update mqtt messages are triggered. We should either update the test script here or create a separate test case that explicitly verifies this. I have added a functional test to check that scene creation and scene updates trigger the cmd_update and consequently a scene creation results in tracker creation.

[ltalarcz]

in review

[ltalarcz]

Please fix trailing hitespace linter issue:

Trailing whitespace: /home/runner/work/scenescape/scenescape/controller/tests/test_database_update_triggers_tracker_creation.py
Trailing whitespace: /home/runner/work/scenescape/scenescape/manager/tests/tc_scene_creation_sends_update.py

NEX-T10448: FAIL

[sbelhaik]

Please fix trailing hitespace linter issue:

Trailing whitespace: /home/runner/work/scenescape/scenescape/controller/tests/test_database_update_triggers_tracker_creation.py Trailing whitespace: /home/runner/work/scenescape/scenescape/manager/tests/tc_scene_creation_sends_update.py

NEX-T10448: FAIL

Done.