Don't persist current tab when display is locked

[shefalijoshi]

…ab displayed

Closes #7871

Describe your changes:

Check if a display is locked before saving current tab. The immutable aspect is handled by openmct.objects.mutate
Add tests

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Is this a notable change that will require a special callout in the release notes? For example, will this break compatibility with existing APIs or projects that consume these plugins?

Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes?
• Has this been smoke tested?
• Have you associated this PR with a type: label? Note: this is not necessarily the same as the original issue.
• Have you associated a milestone with this PR? Note: leave blank if unsure.
• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
• Reviewer has tested changes by following the provided instructions?
• Changes appear not to be breaking changes?
• Appropriate automated tests included?
• Code style and in-line documentation are appropriate?

[akhenry]

LGTM, thanks!

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 57.41%. Comparing base (703186a) to head (30913e2).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/plugins/tabs/components/TabsComponent.vue	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7882      +/-   ##
==========================================
- Coverage   57.60%   57.41%   -0.20%     
==========================================
  Files         676      676              
  Lines       27350    27351       +1     
  Branches     2684     2685       +1     
==========================================
- Hits        15756    15703      -53     
- Misses      11258    11311      +53     
- Partials      336      337       +1     

Flag	Coverage Δ
e2e-ci	62.38% <ø> (+<0.01%)	⬆️
e2e-full	41.81% <ø> (-12.16%)	⬇️
unit	49.28% <0.00%> (-0.04%)	⬇️

Files with missing lines	Coverage Δ
src/ui/layout/BrowseBar.vue	40.33% <ø> (-3.37%)	⬇️
src/plugins/tabs/components/TabsComponent.vue	37.59% <0.00%> (-0.29%)	⬇️

... and 8 files with indirect coverage changes

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