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/resolve-system-proxy/resolve-system-proxy.test.ts

@@ -21,7 +21,7 @@ describe("resolve-system-proxy", () => {
 
     resolveSystemProxyFromElectronMock = asyncFn();
 
-    builder.beforeApplicationStart((mainDi) => {
+    builder.beforeApplicationStart(({ mainDi }) => {
       mainDi.override(
         resolveSystemProxyFromElectronInjectable,
         () => resolveSystemProxyFromElectronMock,