merge default options and the prebuild options provided in ember-cli-build

[BlueCutOfficial]

Recently, the prebuild function has been written in the default-pipeline so we can run the build with Vite requirements by default:

// ember-cli-build.js

- return compatBuild(app, undefined, {
-     staticAddonTrees: true,
-     staticAddonTestSupportTrees: true,
-     staticComponents: true,
-     ...
-   });
+ return prebuild(app);

However, there was an issue with the way prebuild uses the options: If an options object was provided in ember-cli-build.js, this would replace entirely the defaultPrebuildOptions that Vite requires and options like staticAddonTrees and staticEmberSource would be false instead of true, resulting to breaking side effects.

This PR changes prebuild function to always use the defaultPrebuildOptions and extend them with the passed options.

How to test manually

• In tests/vite-app/ember-cli-build.js, do the following change:

- return prebuild(app);
+ return prebuild(app, {});

• Then run the vite-app.
• 👀 The app should run correclty

[mansona]

🎉