Fix display of interactive Matplotlib

[philippjfr]

Ensures the ipympl widget is correctly initialized, allowing the plot to be rendered.

[codecov]

Codecov Report

Attention: Patch coverage is 36.00000% with 16 lines in your changes are missing coverage. Please review.

Project coverage is 82.04%. Comparing base (06f0318) to head (d464c3f).

Files	Patch %	Lines
panel/pane/plot.py	36.00%	16 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6450      +/-   ##
==========================================
- Coverage   82.05%   82.04%   -0.01%     
==========================================
  Files         310      310              
  Lines       45930    45945      +15     
==========================================
+ Hits        37689    37697       +8     
- Misses       8241     8248       +7     

Flag	Coverage Δ
ui-tests	36.54% <20.00%> (+<0.01%)	⬆️
unitexamples-tests	71.57% <36.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

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