mtp: support file creation if edit objects is available

Raul Tambrerequested to merge
tambre/gvfs:mtp_create_samsung into master

The Android extensions imply the edit objects capability which is required for LIBMTP_BeginEditObject(). Samsung phones (e.g. Samsung S23 Ultra) don't advertise the extension for some reason, but do have the capability. Predicate the operation being supported on the capability as we do for many other operations. This fixes copying in many common applications such as Beyond Compare which do it with open()/write()/close().

The GNU extensions fix is a fly-by that I required to get things compiling. I can drop or change if undesireable. Unsure what the correct C version to specify would be.

Edited by Raul Tambre

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