[stable5.0] fix(embed): calendar header overlapping and adjust to compact design

[backportbot]

Backport of PR #6317

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 15.43%. Comparing base (d2b4645) to head (c73279c).
Report is 3 commits behind head on stable5.0.

Additional details and impacted files

@@            Coverage Diff             @@
##           stable5.0    #6319   +/-   ##
==========================================
  Coverage      15.43%   15.43%           
==========================================
  Files            206      206           
  Lines           9442     9442           
  Branches        2194     2205   +11     
==========================================
  Hits            1457     1457           
+ Misses          7667     7666    -1     
- Partials         318      319    +1     

Flag	Coverage Δ
javascript	15.43% <ø> (ø)

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