[Notebooks] UI fixes

[JslYoon]

Hey, I just made a Pull Request!

• Hide notebooks tab when lightspeed.notebooks.enabled: false in config
• Fix notebook queries to display correct model from config instead of chat's selected model
• Add /notebook-conversation-ids endpoint to filter notebook conversations from chat list even when notebooks disabled
• lightspeed doesn't crash when Notebooks is enabled but querydefualts is empty

Addressing bugs:
https://redhat.atlassian.net/browse/RHDHBUGS-3097
https://redhat.atlassian.net/browse/RHDHBUGS-3105
https://redhat.atlassian.net/browse/RHDHBUGS-3098
https://redhat.atlassian.net/browse/RHDHBUGS-3111

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or Updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)

[rhdh-gh-app]

Important

This PR includes changes that affect public-facing API. Please ensure you are adding/updating documentation for new features or behavior.

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@red-hat-developer-hub/backstage-plugin-lightspeed-backend	workspaces/lightspeed/plugins/lightspeed-backend	minor	v2.6.6
@red-hat-developer-hub/backstage-plugin-lightspeed	workspaces/lightspeed/plugins/lightspeed	minor	v2.6.6

[JslYoon]

/review

[codecov]

Codecov Report

❌ Patch coverage is 38.33333% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.26%. Comparing base (fc38238) to head (ee46072).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3062      +/-   ##
==========================================
- Coverage   57.28%   57.26%   -0.03%     
==========================================
  Files        2067     2068       +1     
  Lines       63528    63575      +47     
  Branches    16583    16596      +13     
==========================================
+ Hits        36390    36404      +14     
- Misses      26704    26737      +33     
  Partials      434      434              

Flag	Coverage Δ		*Carryforward flag
adoption-insights	83.58% <ø> (ø)		Carriedforward from 8540578
ai-integrations	70.03% <ø> (ø)		Carriedforward from 8540578
app-defaults	69.60% <ø> (ø)		Carriedforward from 8540578
augment	69.36% <ø> (ø)		Carriedforward from 8540578
bulk-import	72.44% <ø> (ø)		Carriedforward from 8540578
cost-management	16.49% <ø> (ø)		Carriedforward from 8540578
dcm	32.85% <ø> (ø)		Carriedforward from 8540578
extensions	61.71% <ø> (ø)		Carriedforward from 8540578
global-floating-action-button	73.75% <ø> (ø)		Carriedforward from 8540578
global-header	61.68% <ø> (ø)		Carriedforward from 8540578
homepage	50.92% <ø> (ø)		Carriedforward from 8540578
konflux	91.01% <ø> (ø)		Carriedforward from 8540578
lightspeed	69.57% <38.33%> (-0.35%)	⬇️
mcp-integrations	81.59% <ø> (ø)		Carriedforward from 8540578
orchestrator	34.80% <ø> (ø)		Carriedforward from 8540578
quickstart	62.64% <ø> (ø)		Carriedforward from 8540578
sandbox	79.56% <ø> (ø)		Carriedforward from 8540578
scorecard	83.61% <ø> (ø)		Carriedforward from 8540578
theme	64.54% <ø> (ø)		Carriedforward from 8540578
translations	8.49% <ø> (ø)		Carriedforward from 8540578
x2a	17.29% <ø> (ø)		Carriedforward from 8540578

*This pull request uses carry forward flags. Click here to find out more.

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[its-mitesh-kumar]

When notebook is not enabled , there should be no tab, it should be as it was before notebook feature.

[its-mitesh-kumar]

Frontend code changes looks good, Upload the latest screen recording and get the CI pass. Then I will verify it by running it locally.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud