docs(infr): add info about model import duration

Author: bene2k1

pages/managed-inference/how-to/import-custom-model.mdx

@@ -47,5 +47,9 @@ Scaleway provides a selection of common models for deployment from the Scaleway
     - Quantization options.
     - Estimated cost.
    Once checked, click **Begin import** to finalize the process.
+   <Message type="note">
+      Importing a model may take some time, depending on its size. Once the import is complete, the model will appear in the model library.
+   </Message>
+
+Your imported model will now appear in the model library. You can proceed to [deploy your model on Managed Inference](/managed-inference/how-to/create-deployment/).
 
-Your imported model will now appear in the model library. You can proceed to [deploy your model on Managed Inference](/managed-inference/how-to/create-deployment/).