feat: Remove usage of user segment

[AbhiPrasad]

ref getsentry/team-sdks#44

user segment has been deprecated across all the sdks, and was never used for dynamic sampling logic, so it's safe to remove.

[github-actions]

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📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against b99d0d1

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.19%. Comparing base (d8c1066) to head (b99d0d1).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2493      +/-   ##
==========================================
- Coverage   98.19%   98.19%   -0.01%     
==========================================
  Files         128      128              
  Lines        4833     4832       -1     
==========================================
- Hits         4746     4745       -1     
  Misses         87       87              

Components	Coverage Δ
sentry-ruby	98.57% <ø> (-0.01%)	⬇️
sentry-rails	97.07% <ø> (ø)
sentry-sidekiq	97.42% <ø> (ø)
sentry-resque	92.85% <ø> (ø)
sentry-delayed_job	95.65% <ø> (ø)
sentry-opentelemetry	99.31% <ø> (ø)

Files with missing lines	Coverage Δ
sentry-ruby/lib/sentry/propagation_context.rb	100.00% <ø> (ø)
sentry-ruby/lib/sentry/transaction.rb	99.35% <ø> (-0.01%)	⬇️