[MM-39491] Force Add Server modal to stay until server has been added (#1869)

* [MM-39491] Force Add Server modal to stay until server has been added

* Make the parameter optional

* Actually do the logic, add a test for the logic

* Add remove event listener

src/common/communication.ts

@@ -104,3 +104,6 @@ export const GET_AVAILABLE_SPELL_CHECKER_LANGUAGES = 'get-available-spell-checke
 
 export const GET_VIEW_NAME = 'get-view-name';
 export const GET_VIEW_WEBCONTENTS_ID = 'get-view-webcontents-id';
+
+export const GET_MODAL_UNCLOSEABLE = 'get-modal-uncloseable';
+export const MODAL_UNCLOSEABLE = 'modal-uncloseable';