Remove backward compatibility (onSettingsChange callback is async).

server/@types/peertube.d.ts

@@ -17,7 +17,7 @@ interface PluginSettingsManager {
   getSetting: (name: string) => Promise<string | boolean>
   getSettings: (names: string[]) => Promise<{ [settingName: string]: string | boolean }>
   setSetting: (name: string, value: string) => Promise<any>
-  onSettingsChange: (cb: (names: string[]) => void) => void
+  onSettingsChange: (cb: (names: string[]) => Promise<any>) => void
 }
 
 interface PluginStorageManager {