Merge model_cfg & model_kwargs before passing to model, allows SigLIP…

… models to be trained with SigLIP loss via --siglip (avoid dupe arg)

src/open_clip/factory.py

@@ -240,13 +240,14 @@ def create_model(
             model_cfg['text_cfg']['hf_model_pretrained'] = pretrained_hf and not pretrained
         custom_text = model_cfg.pop('custom_text', False) or force_custom_text or is_hf_model
 
+        model_cfg = dict(model_cfg, **model_kwargs)  # merge cfg dict w/ kwargs (kwargs overrides cfg)
         if custom_text:
             if "multimodal_cfg" in model_cfg:
-                model = CoCa(**model_cfg, **model_kwargs, cast_dtype=cast_dtype)
+                model = CoCa(**model_cfg, cast_dtype=cast_dtype)
             else:
-                model = CustomTextCLIP(**model_cfg, **model_kwargs, cast_dtype=cast_dtype)
+                model = CustomTextCLIP(**model_cfg, cast_dtype=cast_dtype)
         else:
-            model = CLIP(**model_cfg, **model_kwargs, cast_dtype=cast_dtype)
+            model = CLIP(**model_cfg, cast_dtype=cast_dtype)
 
         if precision in ("fp16", "bf16"):
             dtype = torch.float16 if 'fp16' in precision else torch.bfloat16