Fix sentry-delayed_job: respect custom max_attempts

[natikgadzhi]

Summary

• Fixes Delayed job plugin misses errors from jobs with custom max_attempts #2076:
• Applies the fix that @claireannecotter proposed, ensuring it's safe.
• Adds specs and the CHANGELOG entry.

/cc @sl0thentr0py are you tired of me yet?

[codecov]

Codecov Report

Merging #2177 (f991b4b) into master (7793e97) will increase coverage by 0.02%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2177      +/-   ##
==========================================
+ Coverage   97.30%   97.33%   +0.02%     
==========================================
  Files          99       99              
  Lines        3680     3681       +1     
==========================================
+ Hits         3581     3583       +2     
+ Misses         99       98       -1     

Components	Coverage Δ
sentry-ruby	98.02% <ø> (ø)
sentry-rails	94.98% <ø> (ø)
sentry-sidekiq	94.50% <ø> (ø)
sentry-resque	93.65% <ø> (+1.58%)	⬆️
sentry-delayed_job	94.44% <100.00%> (+0.07%)	⬆️
sentry-opentelemetry	100.00% <ø> (ø)

Files	Coverage Δ
...entry-delayed_job/lib/sentry/delayed_job/plugin.rb	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

[st0012]

Let's add a changelog entry for this?

[natikgadzhi]

@st0012 yep, I've added it and didn't push it up 🤦🏼. Fixed.