Convert imports to ES6 from CommonJS

This is needed because `require()` means something different in webpack - it ends up importing the module as something we didn't expect (and is occasionally async)

src/autocomplete/CommunityProvider.js

@@ -46,7 +46,7 @@ export default class CommunityProvider extends AutocompleteProvider {
         });
     }
 
-    async getCompletions(query: string, selection: SelectionRange, force?: boolean = false): Array<Completion> {
+    async getCompletions(query: string, selection: SelectionRange, force: boolean = false): Array<Completion> {
         const BaseAvatar = sdk.getComponent('views.avatars.BaseAvatar');
 
         // Disable autocompletions when composing commands because of various issues