[MM-40638] Type all of the websocket event names as a new type WebsocketEventType (#25454)

Co-authored-by: Sudheer Tripathi <sudheer@clearglass.com>
Co-authored-by: Sudheer Tripathi <31629433+sudheer121@users.noreply.github.com>
Co-authored-by: Sudheer Tripathi <tripathisudheer604@gmail.com>

server/channels/app/platform/config_test.go

@@ -79,7 +79,7 @@ func TestConfigSave(t *testing.T) {
 		defer th.TearDown()
 
 		metricsMock := &mocks.MetricsInterface{}
-		metricsMock.On("IncrementWebsocketEvent", mock.AnythingOfType("string")).Return()
+		metricsMock.On("IncrementWebsocketEvent", model.WebsocketEventConfigChanged).Return()
 		metricsMock.On("IncrementWebSocketBroadcastBufferSize", mock.AnythingOfType("string"), mock.AnythingOfType("float64")).Return()
 		metricsMock.On("DecrementWebSocketBroadcastBufferSize", mock.AnythingOfType("string"), mock.AnythingOfType("float64")).Return()
 		metricsMock.On("Register").Return()