bug(supervisor, ttl): worker gets into the inconsistent state after TTL was reached

[rustatian]

Reason for This PR

closes: #748
closes: #740

Description of Changes

• After execution worker should check its state. And if the state is not equal to the StateWorking, that means, that the worker's state was overwritten during the execution by the supervisor. In this case, the worker should return the response w/o error, and should be stopped by the supervisor or worker_watcher.
• Add RR_BROADCAST_PATH to the WebSockets plugin.

License Acceptance

By submitting this pull request, I confirm that my contribution is made under
the terms of the MIT license.

PR Checklist

[Author TODO: Meet these criteria.]
[Reviewer TODO: Verify that these criteria are met. Request changes if not]

• All commits in this PR are signed (git commit -s).
• The reason for this PR is clearly provided (issue no. or explanation).
• The description of changes is clear and encompassing.
• Any required documentation changes (code and docs) are included in this PR.
• Any user-facing changes are mentioned in CHANGELOG.md.
• All added/changed functionality is tested.

[codecov]

Codecov Report

Merging #749 (cb28ad0) into master (7681180) will increase coverage by 0.06%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##           master     #749      +/-   ##
==========================================
+ Coverage   67.58%   67.64%   +0.06%     
==========================================
  Files          94       94              
  Lines        4843     4846       +3     
==========================================
+ Hits         3273     3278       +5     
+ Misses       1156     1154       -2     
  Partials      414      414              

Impacted Files	Coverage Δ
pkg/pool/static_pool.go	80.95% <ø> (ø)
pkg/worker_watcher/container/vec.go	100.00% <ø> (ø)
plugins/websockets/plugin.go	55.68% <33.33%> (ø)
pkg/pool/supervisor_pool.go	87.14% <100.00%> (+3.08%)	⬆️
pkg/worker/sync_worker.go	81.51% <100.00%> (+0.47%)	⬆️
pkg/worker_watcher/worker_watcher.go	81.72% <100.00%> (-0.20%)	⬇️

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