MM-27199 - Add metrics to MM server for total enabled user count (#15116)

* Add metrics to MM server for total enabled user count and include installation ID from a new env var

* diagnostics context

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

einterfaces/metrics.go

@@ -59,5 +59,6 @@ type MetricsInterface interface {
 	ObservePluginMultiHookDuration(elapsed float64)
 	ObservePluginApiDuration(pluginID, apiName string, success bool, elapsed float64)
 
+	ObserveEnabledUsers(users int64)
 	GetLoggerMetricsCollector() logr.MetricsCollector
 }

einterfaces/mocks/MetricsInterface.go

@@ -200,6 +200,11 @@ func (_m *MetricsInterface) ObserveClusterRequestDuration(elapsed float64) {
 	_m.Called(elapsed)
 }
 
+// ObserveEnabledUsers provides a mock function with given fields: users
+func (_m *MetricsInterface) ObserveEnabledUsers(users int64) {
+	_m.Called(users)
+}
+
 // ObservePluginApiDuration provides a mock function with given fields: pluginID, apiName, success, elapsed
 func (_m *MetricsInterface) ObservePluginApiDuration(pluginID string, apiName string, success bool, elapsed float64) {
 	_m.Called(pluginID, apiName, success, elapsed)