[linuxinput] fixes to thing properties (#10634)

[linuxinput] fixes to thing properties (#10634)

* Do not discover on ENTRY_MODIFY

ENTRY_MODIFY is triggered on each keypress multiple times, so we should
not trigger on it.

The usecase for ENTRY_MODIFY triggers where detecting permission changes
of the event nodes.
Inotify does have a dedicate event ("ATTRIB") for that but Java
WatchService normalizes this to a ENTRY_MODIFY event
(See LinuxWatchService.java)

After permission changes users now have to trigger a scan manually.

* Use proper representation property

* Show event node in label

This makes it easier to figure out which thing is which device in the
presence of symlinks or multiple identical devices.

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>