feat(fixtures): Add array support for create_app_fixture(app)

[karangattu]

This pull request includes the following changes

• Previously if a user was using local_app fixture or create_app_fixture(), the only app name that was allowed as app.py. With this change, we now create a new fixture object with many app paths.

Example usage

app = create_app_fixture(["app-core.py", "app-express.py"])

def test_accordion_demo(page: Page, app: ShinyAppProc) -> None:
    page.goto(app.url)

• Also added AI generated Shiny apps with core and express syntax and their corresponding AI generated tests to show the usage as highlighted above.
• Add the directory where all the AI generated code and tests will live to the pyright ignore list