Ensure busy counter is always reset

[philippjfr]

Fixes #6697

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 22.10%. Comparing base (76c911a) to head (b983770).
Report is 1 commits behind head on main.

❗ Current head b983770 differs from pull request most recent head 6c199df. Consider uploading reports for the commit 6c199df to get more accurate results

Files	Patch %	Lines
panel/reactive.py	0.00%	10 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6698       +/-   ##
===========================================
- Coverage   40.01%   22.10%   -17.92%     
===========================================
  Files         313      313               
  Lines       46194    46210       +16     
===========================================
- Hits        18486    10216     -8270     
- Misses      27708    35994     +8286     

Flag	Coverage Δ
ui-tests	?
unitexamples-tests	22.10% <0.00%> (?)

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