/api/speedtest/latest - failed: true should be false

**Describe the bug**
When getting the latest speedtest through the API endpoint, it says "failed" is "true" when it was actually successful.

**To Reproduce**
Navigate to /api/speedtest/latest

**Additional context**
Line 38 of GetLatestController.php is:
'failed' => $latest->successful

I guess that should be:
'failed' => !$latest->successful
