GroupNorm missing from NNX normalization layer

[treigerm]

There's currently no implementation of group normalization in the NNX normalization layers. Is there a specific reason for why it is not implemented at the moment? If not I would be happy to open a PR and implement it.

[cgarciae]

Hey @treigerm, no particular reason other than we haven't gotten to it.
Feel free to send a PR, happy to review it. Take a look at how the other layers have been ported and check the tests for these layers, we check numerical equivalence with Linen layers and tests combinations of parameters.

[treigerm]

Great, will look at the other layers and will send a PR by the end of this week.