[FIX] portal: avoid strange domain when fetch messages

When fetching messages from the portal controller, we might
give a domain to restrict the message selection. Typically,
the ecommerce allows users to submit messages with rating
of the product. Users are allowed to filter the messages
with a certain rating.
Passing a non-normalized domain to this controller could
give strange result, as the code was using `+=` to concat
domains; some result domain could have been correct, but
return some strange results.

This commit normalizes all domains used in the code
making a non-normalized domain (given as parameter) crashes,
instead of returning unexpected messages.

Closes #26939