browser (cache): make `fill_identities` async + use `json` module: - `json` module has been greatly improved in Brython, the former workaround is not needed anymore. - `fill_identities` is now async so an async method can wait for it to complete

"""manage common dialogs"""

from browser import document

def remove_loading_screen():
    print("removing loading screen")
    document['loading_screen'].remove()