Tabs set visibility and opacity on inactive tabs

[philippjfr]

Fixes issues where visibility is overridden on a child element and inactive tabs content still shows up.

[codecov]

Codecov Report

Merging #3329 (4b202e4) into master (c82881a) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3329      +/-   ##
==========================================
- Coverage   83.35%   83.34%   -0.01%     
==========================================
  Files         196      196              
  Lines       26486    26486              
==========================================
- Hits        22078    22076       -2     
- Misses       4408     4410       +2     

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

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c82881a...4b202e4. Read the comment docs.