VReplication: Fix vtctldclient SwitchReads related bugs and move the TestBasicV2Workflows e2e test to vtctldclient#15579

mattlord merged 8 commits intovitessio:mainvitessio/vitess:mainfrom

planetscale:vrepl_v2_vtctldplanetscale/vitess:vrepl_v2_vtctldCopy head branch name to clipboard