Include binary_mem and average ref count in top process metrics

[alco]

Following an investigation in Cloud the other day, we noticed that it's possible to measure process' off-heap binaries separately. So I've added a few data points to our metrics for that.

Also noticed that stack metrics didn't include stack_id, fixed that.

Updated the integration tests for otel export to be more diligent about verifying metric and resource attributes.

Added caching for lux on CI, to avoid refetching it on every test suite run.

[codecov]

Codecov Report

❌ Patch coverage is 70.83333% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.26%. Comparing base (850ad3d) to head (d419585).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ry/lib/electric/telemetry/application_telemetry.ex	0.00%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3621       +/-   ##
===========================================
- Coverage   88.13%   76.26%   -11.87%     
===========================================
  Files          18       30       +12     
  Lines        1643     2018      +375     
  Branches      409      413        +4     
===========================================
+ Hits         1448     1539       +91     
- Misses        193      477      +284     
  Partials        2        2               

Flag	Coverage Δ
electric-telemetry	24.26% <70.83%> (?)
elixir	24.26% <70.83%> (?)
packages/experimental	87.73% <ø> (ø)
packages/react-hooks	86.48% <ø> (ø)
packages/typescript-client	93.76% <ø> (ø)
packages/y-electric	55.66% <ø> (ø)
typescript	88.13% <ø> (ø)
unit-tests	76.26% <70.83%> (-11.87%)	⬇️

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