ConfigurationPrinterAdapter.getMethod should not only consider implementation class

As part of FELIX-3963 the ConfigurationPrinterAdapter.getMethod was modified to not scan the class hierarchy to reflectively find methods to call, such as getTitle, printConfiguration, etc.

While this is fine for most cases, in the particular case of the service implementing the ConfigurationPrinter service, which declares some methods, the class hierarchy should be searched. This would also be in line with Web Console 4 where the method was retrieved from the service interface and not the implementation class.