[release-19.0] Fix vtctldclient SwitchReads related bugs and move the TestBasicV2Workflows e2e test to vtctldclient (#15579)

[vitess-bot]

Description

This is a backport of #15579

Fixes: #15594

[vitess-bot]

Review Checklist

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General

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 32 lines in your changes are missing coverage. Please review.

Project coverage is 67.43%. Comparing base (3ce8f87) to head (584e8b7).

Files	Patch %	Lines
go/vt/vtctl/workflow/traffic_switcher.go	0.00%	17 Missing ⚠️
go/vt/vtctl/workflow/server.go	0.00%	13 Missing ⚠️
...lient/command/vreplication/common/switchtraffic.go	0.00%	1 Missing ⚠️
go/vt/vttablet/tabletmanager/rpc_vreplication.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release-19.0   #15584      +/-   ##
================================================
+ Coverage         67.40%   67.43%   +0.03%     
================================================
  Files              1560     1560              
  Lines            192661   192655       -6     
================================================
+ Hits             129857   129923      +66     
+ Misses            62804    62732      -72     

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