return alerts with null account sid

There are a few alerts raised that do not have an account_sid associated with them, for example options failures on sbc-sip-sidecar where the carrier is availible to all accounts.

These will appear in influx db with the account_sid as null, However there is no way for these alerts to be surfaced to the user.

my proposal is to have the API respond with alerts that contain a null account_sid for all accounts as the alerts will be relevent to all accounts

Start by locating the API endpoint that retrieves alerts and the filtering logic for account_sid. Reproduce an alert with a null account_sid, then verify that it is returned for every account without changing account-specific filtering. Done means these alerts are consistently exposed through the API.

Written by the indexing model from the issue text.