Do not dispatch events if hold value is set

[philippjfr]

Not sure what the thinking here was but we should not be dispatching events if the Document has been set to hold. Holding is a powerful way to batch events and we should not stop users from taking advantage of it.

[codecov]

Codecov Report

Merging #4178 (928ad6e) into master (55fd4b8) will decrease coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4178      +/-   ##
==========================================
- Coverage   83.61%   83.54%   -0.07%     
==========================================
  Files         224      225       +1     
  Lines       33527    33542      +15     
==========================================
- Hits        28032    28022      -10     
- Misses       5495     5520      +25     

Flag	Coverage Δ
ui-tests	37.55% <29.16%> (-0.07%)	⬇️
unitexamples-tests	74.64% <100.00%> (+0.01%)	⬆️

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

Impacted Files	Coverage Δ
panel/io/document.py	56.17% <100.00%> (+0.68%)	⬆️
panel/tests/io/test_document.py	100.00% <100.00%> (ø)
panel/tests/ui/io/test_jupyter_server_extension.py	50.00% <0.00%> (-50.00%)	⬇️
panel/tests/ui/io/test_jupyterlite.py	89.18% <0.00%> (-8.11%)	⬇️
panel/tests/util.py	87.37% <0.00%> (-3.89%)	⬇️
panel/tests/ui/io/test_convert.py	92.92% <0.00%> (-2.66%)	⬇️
panel/tests/conftest.py	87.12% <0.00%> (-1.29%)	⬇️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more