ci: Split formatting checks for TS and Elixir into separate workflows

[alco]

Different commands are used for checking TS and Elixir code formatting and so it makes sense to use different path filters for them. We can vary path filters only at the workflow level, hence the split into separate workflows.

I have also found a problem in the cache keys where, due to incorrect variable interpolation syntax, the hashFiles() function was always returning an empty string.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.69%. Comparing base (c669280) to head (3bea944).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3591      +/-   ##
==========================================
- Coverage   75.79%   75.69%   -0.11%     
==========================================
  Files          51       51              
  Lines        2752     2752              
  Branches      411      411              
==========================================
- Hits         2086     2083       -3     
- Misses        664      667       +3     
  Partials        2        2              

Flag	Coverage Δ
electric-telemetry	22.99% <ø> (+0.27%)	⬆️
elixir	57.47% <ø> (-0.27%)	⬇️
elixir-client	73.94% <ø> (-0.53%)	⬇️
packages/experimental	87.73% <ø> (ø)
packages/react-hooks	86.48% <ø> (ø)
packages/typescript-client	93.80% <ø> (ø)
packages/y-electric	55.66% <ø> (ø)
typescript	88.13% <ø> (ø)
unit-tests	75.69% <ø> (-0.11%)	⬇️

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