Consider implementing a deinit validity check for DebugToggles

[amyoulton]

While using the updated toggles, we've encountered an issue where sometimes the deinit function is trying to deinitialize things that were never initialized. More info on the discovery here:

https://coda.io/d/DebugMenu-Crash-Diagnosis_d7zPrWJLs_X/DebugMenu-Crash-Diagnosis_suQOT#_lulFw

It might be worth considering adding a check to see whether a key exists before we go ahead and remove it!