Fix detecting device type by form factor of client hints

[Nommyde]

Description:

In the method \DeviceDetector\Parser\Device\AbstractDeviceParser::parseClientHints,
condition \array_key_exists($formFactor, $formFactors) is always false because $formFactor is a string and $formFactors keys are integers ($formFactors is a list of strings). If we fix just this condition, then $deviceType gets the string value of self::getDeviceName, but it should be an int (we don't need the getDeviceName call)
Then, if we fix that, we see that 'deviceType' field is never used in the \DeviceDetector\Parser\Device\AbstractDeviceParser::parse method, so we need to fill $this->deviceType with it to get advantage of client hints when nothing else helps to detect device type.

I am not sure if the fixture I created fits your conventions, but it detects the described problems and does its job.