Airflow 2.1.0, Docker

**What happened**:

Users with the Guest role assigned are stuck in a redirect loop once they attempt to login successfully to the web interface.

**What you expected to happen**:

Get minimal access to the dashboard with the appropriate views for a guest role

**How to reproduce it**:
1. Assign a guest role to any user and remove any other roles with the administrator user.
2. Logout from the admin account 
3. Login as the guest user
4. You will notice constant HTTP redirects, and the dashboard will not show up.


airflow/www/views.py
"""Home view."""
        unit_test_mode: bool = conf.getboolean('core', 'UNIT_TEST_MODE')
        if not unit_test_mode and "sqlite" in conf.get("core", "sql_alchemy_conn"):
            db_doc_page = get_docs_url("howto/set-up-database.html")
            flash(
                Markup(
                    "Usage of <b>SQLite</b> detected. It should only be used for dev/testing. "
                    "Do not use <b>SQLite</b> as metadata DB in production. "
                    "We recommend using Postgres or MySQL. "
                    f"<a href='{db_doc_page}'><b>Click here</b></a> for more information."
                ),
                category="warning",
            )
        if not unit_test_mode and conf.get("core", "executor") == "SequentialExecutor":
            exec_doc_page = get_docs_url("executor/index.html")
            flash(
                Markup(
                    "Usage of <b>SequentialExecutor</b> detected. "
                    "Do not use <b>SequentialExecutor</b> in production. "
                    f"<a href='{exec_doc_page}'><b>Click here</b></a> for more information."
                ),
                category="warning",
            )