add error message details

Co-authored-by: Isabella Basso <[email protected]>

Signed-off-by: Matteo Mortari <[email protected]>

clients/python/src/model_registry/_client.py

@@ -247,7 +247,17 @@ def register_hf_model(
         try:
             from huggingface_hub import HfApi, hf_hub_url, utils
         except ImportError as e:
-            msg = "huggingface_hub is not installed"
+            msg = """package `huggingface-hub` is not installed.
+            To import models from Hugging Face Hub, start by installing the `huggingface-hub` package, either directly or as an
+            extra (available as `model-registry[hf]`), e.g.:
+            ```sh
+            !pip install --pre model-registry[hf]
+            ```
+            or
+            ```sh
+            !pip install huggingface-hub
+            ```
+            """
             raise StoreError(msg) from e
 
         api = HfApi()