Ensure Tabulator expanded rows are sized correctly after re-render

[philippjfr]

Fixes #3504

[codecov]

Codecov Report

Merging #3507 (90918ba) into master (18d5e4d) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3507      +/-   ##
==========================================
- Coverage   82.93%   82.92%   -0.01%     
==========================================
  Files         199      199              
  Lines       27211    27211              
==========================================
- Hits        22567    22565       -2     
- Misses       4644     4646       +2     

Impacted Files	Coverage Δ
panel/io/reload.py	69.56% <0.00%> (-2.18%)	⬇️

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