pubsub/rabbit: remove stale TODO

[vangent]

See my comment on the bug.

[codecov]

Codecov Report

Merging #1884 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1884      +/-   ##
==========================================
- Coverage   74.01%   74.01%   -0.01%     
==========================================
  Files          80       80              
  Lines        8895     8898       +3     
==========================================
+ Hits         6584     6586       +2     
  Misses       1838     1838              
- Partials      473      474       +1

Impacted Files	Coverage Δ
pubsub/rabbitpubsub/rabbit.go	74% <ø> (ø)	⬆️
mysql/cloudmysql/cloudmysql.go	70.83% <0%> (-3.08%)	⬇️
postgres/cloudpostgres/cloudpostgres.go	20.22% <0%> (-0.47%)	⬇️
internal/retry/retry.go	100% <0%> (+11.76%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 11dbf5f...1b899fb. Read the comment docs.