Shorten timetable share URL

[winphong]

Context

This PR fixes #2057 where timetable share url is not shortened

Implementation

Loading spinner while url is being shortened

Display show original URL button when URL is shortened

NOTE: Used a separate url shortener service to mock url shortening behaviour

Display shorten URL button when URL is full

URL shortening errored

Other Information

👋🏻 my first time contributing to a project, implemented the solution based on my personal experience on user experience, open to suggestion if there's a better UX. Tried my best but not too familiar with UI test so do let me know if there's something that I can improve on. Thanks 🙏🏻

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[codecov]

Codecov Report

Merging #3367 (7cb3921) into master (1160b6f) will increase coverage by 0.18%.
The diff coverage is 96.29%.

@@            Coverage Diff             @@
##           master    #3367      +/-   ##
==========================================
+ Coverage   53.08%   53.27%   +0.18%     
==========================================
  Files         270      270              
  Lines        5745     5757      +12     
  Branches     1327     1332       +5     
==========================================
+ Hits         3050     3067      +17     
+ Misses       2695     2690       -5     

Impacted Files	Coverage Δ
website/src/featureFlags.ts	100.00% <ø> (ø)
website/src/views/timetable/ShareTimetable.tsx	81.42% <96.29%> (+13.00%)	⬆️

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[li-kai]

Thanks for the great work, and apologies for the delay. The code and tests look good to me. @chrisgzf I'll leave the merging to you? We should also open a task to bring our url shorterner back up.