feat: Use the partition watching publisher in the cps client

[palmere-google]

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Fixes #<issue_number_goes_here> ☕️

[codecov]

Codecov Report

Merging #409 (83ab80c) into master (0e4cb93) will decrease coverage by 0.02%.
The diff coverage is 83.33%.

@@             Coverage Diff              @@
##             master     #409      +/-   ##
============================================
- Coverage     71.70%   71.68%   -0.03%     
- Complexity      814      840      +26     
============================================
  Files           156      158       +2     
  Lines          4404     4400       -4     
  Branches        219      223       +4     
============================================
- Hits           3158     3154       -4     
+ Misses         1126     1125       -1     
- Partials        120      121       +1     

Impacted Files	Coverage Δ	Complexity Δ
...loud/pubsublite/internal/wire/RoutingMetadata.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...google/cloud/pubsublite/beam/PublisherOptions.java	25.00% <0.00%> (+1.47%)	4.00 <0.00> (ø)
...loud/pubsublite/cloudpubsub/PublisherSettings.java	68.75% <83.33%> (-31.25%)	5.00 <0.00> (-2.00)
...oud/pubsublite/cloudpubsub/SubscriberSettings.java	89.36% <100.00%> (-0.23%)	12.00 <0.00> (ø)
...gle/cloud/pubsublite/internal/AdminClientImpl.java	100.00% <100.00%> (ø)	18.00 <2.00> (ø)
...loud/pubsublite/internal/TopicStatsClientImpl.java	100.00% <100.00%> (ø)	3.00 <0.00> (ø)
...loud/pubsublite/internal/wire/AssignerBuilder.java	65.38% <100.00%> (-1.29%)	3.00 <0.00> (ø)
...oud/pubsublite/internal/wire/CommitterBuilder.java	52.63% <100.00%> (-2.37%)	2.00 <0.00> (ø)
...oud/pubsublite/internal/wire/PublisherBuilder.java	62.26% <100.00%> (ø)	3.00 <0.00> (ø)
...ud/pubsublite/internal/wire/SubscriberBuilder.java	40.74% <100.00%> (-2.12%)	2.00 <0.00> (ø)
... and 46 more

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