DEV: Switch to new addComposerToolbarPopupMenuOption plugin API (#66)

Why this change?

`api.addToolbarPopupMenuOptionsCallback` has been deprecated in https://github.com/discourse/discourse/commit/913fd3a7b392b492f6344102577960a6eada00ce

javascripts/discourse/api-initializers/table-builder.js

@@ -1,30 +1,19 @@
 import { apiInitializer } from "discourse/lib/api";
 import SpreadsheetEditor from "../components/spreadsheet-editor";
-import { action } from "@ember/object";
-import { inject as service } from "@ember/service";
 
-export default apiInitializer("0.11.1", (api) => {
-  api.modifyClass("controller:composer", {
-    pluginId: "discourse-table-builder",
-    modal: service(),
+export default apiInitializer("1.15.0", (api) => {
+  const modal = api.container.lookup("service:modal");
 
-    @action
-    showTableBuilder() {
-      this.modal.show(SpreadsheetEditor, {
+  api.addComposerToolbarPopupMenuOption({
+    icon: "table",
+    label: themePrefix("discourse_table_builder.composer.button"),
+    action: (toolbarEvent) => {
+      modal.show(SpreadsheetEditor, {
         model: {
-          toolbarEvent: this.toolbarEvent,
+          toolbarEvent,
           tableTokens: null,
         },
       });
     },
   });
-
-  api.addToolbarPopupMenuOptionsCallback(() => {
-    return {
-      id: "table-builder",
-      action: "showTableBuilder",
-      icon: "table",
-      label: themePrefix("discourse_table_builder.composer.button"),
-    };
-  });
 });