Fix Light Link default group name too long

[elupus]

This fixes the following error that occurs hidden in debug logs in tests:

    | Traceback (most recent call last):
    |   File "/Users/joakim/src/hass/zha/zha/zigbee/endpoint.py", line 200, in caller
    |     await getattr(ch, func_name)(*args)
    |   File "/Users/joakim/src/hass/zha/zha/zigbee/cluster_handlers/lightlink.py", line 48, in async_configure
    |     await coordinator.add_to_group(0x0000, name="Default Lightlink Group")
    |   File "/Users/joakim/src/hass/zigpy/zigpy/device.py", line 294, in add_to_group
    |     await ep.add_to_group(grp_id, name)
    |   File "/Users/joakim/src/hass/zigpy/zigpy/endpoint.py", line 149, in add_to_group
    |     res = await self.groups.add(grp_id, name)
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   File "/Users/joakim/src/hass/zigpy/zigpy/zcl/__init__.py", line 357, in request
    |     hdr, request = self._create_request(
    |                    ^^^^^^^^^^^^^^^^^^^^^
    |   File "/Users/joakim/src/hass/zigpy/zigpy/zcl/__init__.py", line 320, in _create_request
    |     request.serialize()  # Throw an error before generating a new TSN
    |     ^^^^^^^^^^^^^^^^^^^
    |   File "/Users/joakim/src/hass/zigpy/zigpy/types/struct.py", line 261, in serialize
    |     chunks.append(value.serialize())
    |                   ^^^^^^^^^^^^^^^^^
    |   File "/Users/joakim/src/hass/zigpy/zigpy/types/basic.py", line 983, in serialize
    |     raise ValueError(f"String is too long (>{self._max_len})")
    | ValueError: String is too long (>16)

Source of limitation: https://github.com/zigpy/zigpy/blob/925a112b8f64685164c7cbc89479a3ad76b9b5a1/zigpy/zcl/clusters/general.py#L613

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.68%. Comparing base (dfe5ae7) to head (1b55527).
Report is 8 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #129      +/-   ##
==========================================
+ Coverage   95.65%   95.68%   +0.03%     
==========================================
  Files          61       61              
  Lines        9255     9255              
==========================================
+ Hits         8853     8856       +3     
+ Misses        402      399       -3     

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[dmulcahey]

Should we just clamp the name to 16 characters when interacting w/ the ZCL layer?

[puddly]

We could use a UUID and map the group name in the database.

[dmulcahey]

We could use a UUID and map the group name in the database.

I wonder... do we even need to supply the name in the cluster command? We already have the name and group id in the db...

[TheJulianJES]

That group name is just for devices, yeah. Some don't even support keeping the group name and I don't think they're actually used anyway.
I'd just trim the name when sending it to the device or not send it at all.

[TheJulianJES]

Let's include this for now. We can implement further changes (of completely capping the group names, or even removing them entirely, for ZCL) in the future.