fix(cli)!: protect client Logger and refactor cli scaletest tests (#8317)

- (breaking) Protects Logger and LogBodies fields of codersdk.Client with its mutex. This addresses a data race in cli/scaletest.
- Fillets the existing cli/createworkspaces unit test and moves the testing logic there into the tests under scaletest/createworkspaces.
- Adds testutil.RaceEnabled bool const and conditionaly skips previously-skipped tests under scaletest/ if the race detector is enabled. This is unfortunate and sad, but I would prefer to have these tests at least running without the race detector than not running at all.
- Adds IgnoreErrors option to fake in-memory agent loggers; having the agents fail the test immediately when they encounter any sort of error isn't really helpful.

cli/ssh_test.go

@@ -49,7 +49,7 @@ func setupWorkspaceForAgent(t *testing.T, mutate func([]*proto.Agent) []*proto.A
 		}
 	}
 	client := coderdtest.New(t, &coderdtest.Options{IncludeProvisionerDaemon: true})
-	client.Logger = slogtest.Make(t, nil).Named("client").Leveled(slog.LevelDebug)
+	client.SetLogger(slogtest.Make(t, nil).Named("client").Leveled(slog.LevelDebug))
 	user := coderdtest.CreateFirstUser(t, client)
 	agentToken := uuid.NewString()
 	version := coderdtest.CreateTemplateVersion(t, client, user.OrganizationID, &echo.Responses{