Remove usage of columns argument in arch detection since old LTS systems may not have that flag.

LTS linux distros like Ubuntu 18.04 have an older flatpak that doesn't have the list argument for specific columns. This makes any newer KDevelop run on this distro(ex. AppImages) try to run a command for a newer version of Flatpak than is on that distro. This patch aims to find a middle ground on using the updated code while also trying to not break the ability to use flatpak on the latest LTS distros. This includes remove the columns argument and the requirement of matching the end of the regexp(since there are other columns on the full output). A quick regexp test shows this matches the multi column output in the older version.