[C++][CI] Remove outdated Github Actions ARM builds #28901
Description
We used to have ARM self-hosted workers configured for GHA. These builds are permanently set to disabled, we should rather remove those jobs to reduce the noise both in the configuration file and the PR checks.
Reporter: Krisztian Szucs / @kszucs
Assignee: Krisztian Szucs / @kszucs
PRs and other links:
Note: This issue was originally created as ARROW-13211. Please see the migration documentation for further details.