fix(browser): Stub a .ts file to allow Angular AOT mode to recompile

[bengourley]

In Angular's AOT mode, the first full build would work but an incremental build upon making a change
would fail with an error that it couldn't locale the bugsnag browser types module. By generating an
empty bugsnag.ts file in the browser/dist/types directory, Angular is convinced that it's ok and it
all compiles and runs correctly.

Additionally this removes the stubbed types on the Bugsnag object – in none of my test permutations were these needed. Update: I found that it was required in the end.

Fixes #523

Testing

Create a new angular app npx ng new test-ng-app and integrate Bugsnag according to the docs.

Run it with ng serve --aot and once it's running, save one of the source files to trigger a rebuild. Notice this error:

ERROR in ./src/app/app.module.ngfactory.js
Module not found: Error: Can't resolve '@bugsnag/browser/dist/types/bugsnag' in '/Users/user/dev/ng-app/src/app'

Now switch over to this repository and checkout this branch.

Ensure the dependencies are installed and the standalone modules are built:

npm run bootstrap
npm run build

Prepare a tarball of the browser notifier:

cd packages/browser
npm pack

Switch back to the test-ng-app directory and install the tarball that was just created npm install ../../path-to-bugsnag-js/packages/browser/bugsnag-browser-6.2.0.tgz.

Run the app again with ng serve --aot and once it's running, save one of the source files to trigger a rebuild. Notice that the error does not occur.

[sazap10]

LGTM, works as expected.