Warn on Webserver when using ``SQLite`` or ``SequentialExecutor`` (#17133)
Warn on Webserver when using ``SQLite`` or ``SequentialExecutor`` (#17133)

Context: https://lists.apache.org/thread.html/r07e83f2462f08c4a52f6428b771a07e067ce9272b6256dca470a87fc%40%3Cdev.airflow.apache.org%3E
Note: Red flashes are for errors, we shouldn't use that.
nathanielvarona/airflow,apache/airflow,Acehaidrey/incubator-airflow,apache/airflow,lyft/incubator-airflow,dhuang/incubator-airflow,mistercrunch/airflow,apache/airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,lyft/incubator-airflow,nathanielvarona/airflow,Acehaidrey/incubator-airflow,mistercrunch/airflow,cfei18/incubator-airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,apache/incubator-airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,apache/airflow,dhuang/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,mistercrunch/airflow,bolkedebruin/airflow,bolkedebruin/airflow,nathanielvarona/airflow,apache/incubator-airflow,bolkedebruin/airflow,dhuang/incubator-airflow,apache/airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,apache/incubator-airflow,apache/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,apache/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow