Improve messaging when taking screenshots if unsupported

[nwhite-riot]

Not all platforms support taking screenshots, so it'd be useful to improve the debug messaging etc. instead of what we currently have here:

sentry-unreal/plugin-dev/Source/Sentry/Private/Utils/SentryScreenshotUtils.cpp

Lines 42 to 46 in 0399872

	if (!(IsInGameThread() || IsInSlateThread()))
	{
	UE_LOG(LogSentrySdk, Error, TEXT("Can't take a screenshot when not in the game thread or slate thread"));
	return false;
	}

Perhaps we can have a CanTakeScreenshot() method and then log "unsupported platform" or something, or even omit the attempt to capture screenshot if it isn't supported.

[linear]

UNREAL-87 Improve messaging when taking screenshots if unsupported