932383: utils.py: query dpkg status with unambiguous package name

Querying dpkg status for a binary package without arch qualifier does not work when binaries for multiple architectures are installed. This breaks local package installation detection in reportbug in such cases, leading to unnecessary and confusing user prompts.

Fix this by using dpkg-query -W to append the arch qualifier if needed. This means reportbug will use the first architecture listed by dpkg if the user does not specify otherwise.