fix: plotly regression

[hoxbro]

Description

Fixes #8470

How Has This Been Tested?

Running the original issue code locally and CI.

AI Disclosure

• This PR contains AI-generated content.
  • I have tested all AI-generated content in my PR.
  • I take responsibility for all AI-generated content in my PR.

Tools: Claude code for making an MRE and adding the UI test.

Checklist

• Tests added and is passing

[codecov]

Codecov Report

❌ Patch coverage is 96.55172% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 86.18%. Comparing base (fb924e0) to head (8dfce2a).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
panel/tests/ui/pane/test_plotly.py	94.73%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #8471       +/-   ##
===========================================
+ Coverage   70.44%   86.18%   +15.74%     
===========================================
  Files         348      349        +1     
  Lines       55025    55048       +23     
===========================================
+ Hits        38760    47442     +8682     
+ Misses      16265     7606     -8659     

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[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.