Mark speedtest as scheduled when triggered using the API

[alexjustesen]

📃 Description

This PR restores notification channels for API triggered speed tests by marking the result as "scheduled". Additionally the logic has been updated to reflect the following for user database notifications:

🤔 Logic

• A user who dispatches a speed test, through the API or manually from the dashboard (scheduled and unscheduled):
  • will get a database notification when the test has completed or has failed.
• A user who dispatches a speed test, through the API (scheduled):
  • will get a database notification if benchmark(s) are set and any benchmark is unhealthy.
• A user who dispatches a speed test, manually from the dashboard (unscheduled):
  • will NOT get a database notification if benchmark(s) are set and any benchmark is unhealthy.
• Any speed test that is "unscheduled":
  • will NOT send a notification through enabled notification channels (Apprise, database, mail or webhooks).

🙋‍♂️ FAQ

• Why aren't notifications sent to enabled channels when they're dispatched manually?
  • Now that the API is considered "scheduled", since this is likely coming from an automation, you're dispatching a test while in the application. To reduce noise the system won't blast out notifications to 3rd party integrations.
• Are integrations with data platforms like InfluxDB and Prometheus effected?
  • Nope, data will continue to flow to these system regardless if the speed test was dispatched scheduled or unscheduled.