Change typing for after/before window/application start (#7342)

- Now the callback is provided with an object containing either
  `mainDi` or `windowDi` fields. This should help with confusion
  over which environment the `di` is for

Signed-off-by: Sebastian Malton <sebastian@malton.name>

packages/core/src/features/application-menu/application-menu-in-legacy-extension-api.test.ts

@@ -18,20 +18,18 @@ describe("application-menu-in-legacy-extension-api", () => {
   beforeEach(async () => {
     builder = getApplicationBuilder();
 
-    builder.beforeApplicationStart(
-      (mainDi) => {
-        runInAction(() => {
-          mainDi.register(
-            someTopMenuItemInjectable,
-            someNonExtensionBasedMenuItemInjectable,
-          );
-        });
+    builder.beforeApplicationStart(({ mainDi }) => {
+      runInAction(() => {
+        mainDi.register(
+          someTopMenuItemInjectable,
+          someNonExtensionBasedMenuItemInjectable,
+        );
+      });
 
-        logErrorMock = jest.fn();
+      logErrorMock = jest.fn();
 
-        mainDi.override(logErrorInjectable, () => logErrorMock);
-      },
-    );
+      mainDi.override(logErrorInjectable, () => logErrorMock);
+    });
 
     await builder.startHidden();
   });

packages/core/src/features/application-menu/application-menu.test.ts

@@ -20,7 +20,7 @@ describe.each(allPlatforms)("application-menu, given platform is '%s'", (platfor
 
     builder = getApplicationBuilder();
 
-    builder.beforeApplicationStart((mainDi) => {
+    builder.beforeApplicationStart(({ mainDi }) => {
       mainDi.override(platformInjectable, () => platform);
 
       mainDi.override(

packages/core/src/features/application-menu/handling-of-orphan-application-menu-items.test.ts

@@ -25,7 +25,7 @@ describe("handling-of-orphan-application-menu-items, given orphan menu item", ()
 
     builder = getApplicationBuilder();
 
-    builder.beforeApplicationStart((mainDi) => {
+    builder.beforeApplicationStart(({ mainDi }) => {
       const someOrphanMenuItemInjectable = getInjectable({
         id: "some-orphan-menu-item",
         instantiate: () => ({