Enable combobox for IBM WatsonX URL input fields

Added the 'combobox=True' option to the IBM WatsonX URL input fields in both EmbeddingModelComponent and LanguageModelComponent to enhance user input flexibility.

src/lfx/src/lfx/components/models_and_agents/embedding_model.py

@@ -76,6 +76,7 @@ class EmbeddingModelComponent(LCEmbeddingsModel):
             value=IBM_WATSONX_URLS[0],
             show=False,
             real_time_refresh=True,
+            combobox=True,
         ),
         DropdownInput(
             name="model",

src/lfx/src/lfx/components/models_and_agents/language_model.py

@@ -105,6 +105,7 @@ def fetch_ibm_models(base_url: str) -> list[str]:
             value=IBM_WATSONX_URLS[0],
             show=False,
             real_time_refresh=True,
+            combobox=True,
         ),
         StrInput(
             name="project_id",