Missing values in series with statuscake_test_performance_ms

[frenchviking]

Hello,

First thank you for your work on this exporter. I'm having an issue with one of the metrics, and only one. statuscake_test_performance_ms

My series are missing values resulting to a swiss cheese.

I'm not having this issue with the other metrics so I guess I'm not hitting a timeout or a api call throttling. From the logs I'm having the same issue as #15 .

Let me know if you need anything else to drill down the issue.