chore: remove workspace ack in multitenant setup [PIPE-474]

[BonapartePC]

Description

remove workspace ack in multitenant setup since server serves all the workspaces not just workspaces from scheduler

Linear Ticket

https://linear.app/rudderstack/issue/PIPE-474/cleanup-workspaces-ack-code-from-server

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (6583364) 71.78% compared to head (e4d9b6d) 71.80%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4066      +/-   ##
==========================================
+ Coverage   71.78%   71.80%   +0.01%     
==========================================
  Files         372      371       -1     
  Lines       54984    54858     -126     
==========================================
- Hits        39472    39392      -80     
+ Misses      13187    13153      -34     
+ Partials     2325     2313      -12     

Files	Coverage Δ
app/cluster/dynamic.go	53.20% <ø> (-1.44%)	⬇️
app/cluster/state/etcd.go	57.57% <ø> (-5.89%)	⬇️
app/cluster/state/static.go	100.00% <ø> (ø)

... and 13 files with indirect coverage changes

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