Add get_trace_propagation_meta helper

[sl0thentr0py]

closes #1905

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.66%. Comparing base (186b1e4) to head (8ec13ef).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2314      +/-   ##
==========================================
- Coverage   98.67%   98.66%   -0.01%     
==========================================
  Files         205      205              
  Lines       13329    13339      +10     
==========================================
+ Hits        13152    13161       +9     
- Misses        177      178       +1     

Components	Coverage Δ
sentry-ruby	99.03% <100.00%> (+<0.01%)	⬆️
sentry-rails	97.37% <ø> (ø)
sentry-sidekiq	96.98% <ø> (ø)
sentry-resque	96.76% <ø> (-0.33%)	⬇️
sentry-delayed_job	98.91% <ø> (ø)
sentry-opentelemetry	100.00% <ø> (ø)

Files	Coverage Δ
sentry-ruby/lib/sentry-ruby.rb	96.65% <100.00%> (+0.04%)	⬆️
sentry-ruby/lib/sentry/hub.rb	99.39% <100.00%> (+0.01%)	⬆️
sentry-ruby/spec/sentry_spec.rb	99.85% <100.00%> (+<0.01%)	⬆️

... and 1 file with indirect coverage changes

[bitsandfoxes]

LGTM!