MM-29709 Client side feature flags (#16212)

* Client side feature flags.

* Fix test.

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

config/client.go

@@ -334,5 +334,9 @@ func GenerateLimitedClientConfig(c *model.Config, telemetryID string, license *m
 		}
 	}
 
+	for key, value := range featureFlagsToMap(c.FeatureFlags) {
+		props["FeatureFlag"+key] = value
+	}
+
 	return props
 }