cannot save edits to a blobstore with whitespace in the name

1. Create an S3 blobstore with name "Special Name". Save. This is successful.
2. Edit the same blobstore. Change the Expiration field to a different value. Try to Save.

Save fails with a message "Renaming an S3 blob store name is not supported" indicating the blobstore name cannot be changed, even though there is no field to change the blobstore name and it wasn't changed.

The UI suggests what is happening is that whitespace in the name is URL encoded to a different value and this is causing the error.

Expected

Should be able to edit an existing blobstore with a whitespace or other allowed name characters that might not be URL safe, in the name.