fix missed etcd unregister data case for an existing container in container proxy

[bdoyle0182]

Description

I think this may be an additional case that was missed where the container proxy can shutdown without removing the container data from etcd.

Related issue and scope

• I opened an issue to propose and discuss this change (#????)

My changes affect the following components

• API
• Controller
• Message Bus (e.g., Kafka)
• Loadbalancer
• Scheduler
• Invoker
• Intrinsic actions (e.g., sequences, conductors)
• Data stores (e.g., CouchDB)
• Tests
• Deployment
• CLI
• General tooling
• Documentation

Types of changes

• Bug fix (generally a non-breaking change which closes an issue).
• Enhancement or new feature (adds new functionality).
• Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• I signed an Apache CLA.
• I reviewed the style guides and followed the recommendations (Travis CI will check :).
• I added tests to cover my changes.
• My changes require further changes to the documentation.
• I updated the documentation where necessary.

[bdoyle0182]

@style95 would it be safe to call UnregisterData again from one central place when the container proxy is stopped in Removing to guarantee that the the entries are always unregistered? Would it be an issue if UnregisterData is called twice or would this be a good additional safeguard for me to add?

[codecov-commenter]

Codecov Report

Merging #5390 (f5b9c05) into master (60ca660) will decrease coverage by 10.43%.
The diff coverage is 100.00%.

❗ Current head f5b9c05 differs from pull request most recent head abc82fc. Consider uploading reports for the commit abc82fc to get more accurate results

@@             Coverage Diff             @@
##           master    #5390       +/-   ##
===========================================
- Coverage   76.91%   66.49%   -10.43%     
===========================================
  Files         240      240               
  Lines       14588    14593        +5     
  Branches      629      631        +2     
===========================================
- Hits        11221     9704     -1517     
- Misses       3367     4889     +1522     

Impacted Files	Coverage Δ
...ntainerpool/v2/FunctionPullingContainerProxy.scala	78.65% <100.00%> (+0.17%)	⬆️

... and 34 files with indirect coverage changes

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[style95]

@bdoyle0182
I believe handling UnregisterData is idempotent in the watcher service and it's fine to send multiple times.
If it could be a good safeguard we can add it.

[bdoyle0182]

well this one passed at least somehow so i'm going to go ahead and merge this in...