[stable4.7] fix: appointment slots start and end time

[backportbot]

Backport of #6499

Warning, This backport's changes differ from the original and might be incomplete ⚠️

Todo

• Review and resolve any conflicts
• Amend HEAD commit to remove the line stating to skip CI

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 15.51%. Comparing base (dc91540) to head (6244a90).
Report is 3 commits behind head on stable4.7.

Additional details and impacted files

@@            Coverage Diff             @@
##           stable4.7    #6503   +/-   ##
==========================================
  Coverage      15.51%   15.51%           
==========================================
  Files            206      206           
  Lines           9256     9256           
  Branches        1931     1931           
==========================================
  Hits            1436     1436           
  Misses          7820     7820           

Flag	Coverage Δ
javascript	15.51% <ø> (ø)

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