fix webWails undefined functions

frontend/src/webWails.js

@@ -48,6 +48,8 @@ if (!window.go) {
   // not implemented
   defineApp('AddToDownloadList', async () => {
   })
+  defineApp('CloseMidiPort', async () => {
+  })
   defineApp('ContinueDownload', async () => {
   })
   defineApp('ConvertData', async () => {
@@ -74,8 +76,12 @@ if (!window.go) {
   })
   defineApp('OpenFileFolder', async () => {
   })
+  defineApp('OpenMidiPort', async () => {
+  })
   defineApp('PauseDownload', async () => {
   })
+  defineApp('PlayNote', async () => {
+  })
   defineApp('ReadFileInfo', async () => {
   })
   defineApp('RestartApp', async () => {