Custom Bokeh's TextAreaInput with auto_grow param

[ahuang11]

Adds the initial plumbing, but I couldn't get it working:

Not sure how I debug this. I tried ripping out a lot of the parts in the ts file, but to no avail. I might be missing something really simple.

[codecov]

Codecov Report

Merging #5591 (47cfab4) into chat_components (e935f8b) will decrease coverage by 57.30%.
The diff coverage is 34.88%.

@@                 Coverage Diff                  @@
##           chat_components    #5591       +/-   ##
====================================================
- Coverage            81.45%   24.15%   -57.30%     
====================================================
  Files                  278      280        +2     
  Lines                40971    41202      +231     
====================================================
- Hits                 33372     9953    -23419     
- Misses                7599    31249    +23650     

Flag	Coverage Δ
ui-tests	?
unitexamples-tests	24.15% <34.88%> (-47.71%)	⬇️

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

Files	Coverage Δ
panel/models/__init__.py	100.00% <ø> (ø)
panel/models/widgets.py	100.00% <100.00%> (ø)
panel/widgets/input.py	43.06% <100.00%> (-52.35%)	⬇️
panel/tests/ui/widgets/test_input.py	11.57% <15.15%> (-87.85%)	⬇️

... and 221 files with indirect coverage changes

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

[philippjfr]

Going to close this PR. It should target master not the chat_components PR.