Verify migrations have monotonically increasing version numbers

[Nateowami]

I'm fairly certain there's a way to do this at compile time with the type system, but doing a runtime check is much easier to implement.

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This change is 

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 2 lines in your changes missing coverage. Please review.

Project coverage is 80.84%. Comparing base (dc0b712) to head (4a78f2b).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/RealtimeServer/common/migration.ts	75.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2916      +/-   ##
==========================================
- Coverage   80.84%   80.84%   -0.01%     
==========================================
  Files         532      532              
  Lines       31107    31119      +12     
  Branches     5062     5042      -20     
==========================================
+ Hits        25149    25158       +9     
- Misses       5208     5210       +2     
- Partials      750      751       +1     

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[RaymondLuong3]

Thanks for adding this. I can confirm that an error appears when I list the migrations and they are not in increasing order. I'll note that this will not catch an issue if a migration class is missing.

Reviewed 10 of 10 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Nateowami)