Hide "Delete dashboard" button for default dashboard

[johannaengland]

Dependent on #3233. Another potential part of the fix for #3150.

This hides the "Delete dashboard" button for the default dashboard. Up for discussion if this is how we want to prevent the user from trying to delete the default dashboard.

But this is how it is done for the case where the current dashboard is the last dashboard.

Before:

After:

[sonarcloud]

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

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	991		0	12.61s
✅ PYTHON	ruff	987		0	0.1s

See detailed report in MegaLinter reports

MegaLinter is graciously provided by

[github-actions]

Test results

    9 files      9 suites   8m 57s ⏱️
2 141 tests 2 141 ✅ 0 💤 0 ❌
4 021 runs  4 021 ✅ 0 💤 0 ❌

Results for commit 9dd0596.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.40%. Comparing base (1162b47) to head (9dd0596).

Additional details and impacted files

@@                       Coverage Diff                        @@
##           bugfix/delete-default-dashboard    #3234   +/-   ##
================================================================
  Coverage                            60.40%   60.40%           
================================================================
  Files                                  605      605           
  Lines                                43689    43689           
  Branches                                48       48           
================================================================
  Hits                                 26389    26389           
  Misses                               17288    17288           
  Partials                                12       12           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles

[stveit]

Discovered one problem: If you are in the settings for a dashboard that can be deleted (so the button is shown), then you change it to become the default dashboard, then the delete button is still there and can be clicked

[johannaengland]

Discovered one problem: If you are in the settings for a dashboard that can be deleted (so the button is shown), then you change it to become the default dashboard, then the delete button is still there and can be clicked

Ooof, that means I have to look at the javascript code again 😅