convert : yield Mamba2Model/GraniteMoeModel modify_tensors (ggml-org#19157)

* convert : yield Mamba2Model/GraniteMoeModel modify_tensors

This commit updates the `GraniteHybridModel` class' modify_tensors
function to properly delegate to `Mamba2Model.modify_tensors` and
`GraniteMoeModel.modify_tensors` using 'yield from' instead of 'return'.

The motivation for this is that modify_tensors is a generator function
(it uses 'yield from'), but the two calls above use return statements
but don't yield anything which means that the the caller of this
function will not receive any yielded values from it. And this causes
layer tensors to be silently dropped during conversion.

Author: danbev

convert_hf_to_gguf.py

@@ -8912,13 +8912,16 @@ def modify_tensors(
             name.endswith("block_sparse_moe.input_linear.weight")
             or "shared_mlp" in name
         ):
-            return GraniteMoeModel.modify_tensors(self, data_torch, name, bid)
+            yield from GraniteMoeModel.modify_tensors(self, data_torch, name, bid)
+            return
 
         # Determine whether this is a mamba layer or an attention layer
         if bid in self._ssm_layers:
-            return Mamba2Model.modify_tensors(self, data_torch, name, bid)
+            yield from Mamba2Model.modify_tensors(self, data_torch, name, bid)
+            return
         elif bid in self._attn_layers:
-            return GraniteMoeModel.modify_tensors(self, data_torch, name, bid)
+            yield from GraniteMoeModel.modify_tensors(self, data_torch, name, bid)
+            return
         yield from ModelBase.modify_tensors(self, data_torch, name, bid)
 
     def set_gguf_parameters(self):