Enforce that TP > 1 is not supported for Mamba2 if Quantization is Enabled.

[fabianlim]

Currently there is a bug in the logic that will fail to load the model if the mamba2 layer is quantised. This is because quantised layers have parameters of type ModelWeightParameter that do not allow the weight_loader to be modified, which is our current strategy of handling TP for the mamba2 in_proj, see #13660.

This PR prevents an Attribute Error

AttributeError: property 'weight_loader' of 'ModelWeightParameter' object has no deleter

from being thrown, in the case when using quant layers with TP=1. And also, it prevents TP > 2 from being used if quant layers are present

cc: @tlrmchlsmth

[github-actions]

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