Fix Ikea Rodret group bindings/button events

[SwoopX]

There was a case described on Discord where the dimmer apparently did not fire any button events and there were also no traces of any button presses in the debug log. With the modifications of the DDF and a re-pair of the device, the device was brought to a working state.

Presumably, the added meta item was missing and required to actually make the bindings work. However, this is just a guess, as I'm not fully sure about its importance.

[manup]

Yeah the DDF group setup/interaction is an odd feature and needs some better documentation.

The best description for meta group.endpoints so far is in:

deconz-rest-plugin/de_web_plugin.cpp

Lines 4273 to 4281 in 7f16cda

	/*! On reception of an group command, check that the config.group entries are set properly.
	- This requires the DDF has { "meta": { "group.endpoints": [<endpoints>] }} set,
	or as alternative the DDF has group bindings specified.
	- This takes into account if there are also matching bindings set in the DDF.
	- "auto" entries are replaced based on the index in group.ednpoints.
	- Existing group entries are replaced if the device hasn't configured bindings in the DDF.
	*/
	void DEV_CheckConfigGroupIndication(Resource *rsub, uint8_t srcEndpoint, uint dstGroup, const DeviceDescription::SubDevice &ddfSubDevice)