* Update 4-connection-checking.md As discussed in https://airbytehq-team.slack.com/archives/C02UQ9MJ4GG/p1655312684160609 - this example is misleading, as it does not actually connect to any API to validate connectivity. * Update 4-connection-checking.md Added a link to OneSignal check_connection, and move the "Note" to below the example