ci : renable arm64 docker builds (#3832)

This commit re-enables the arm64 docker images builds which were removed
in Commit 9366544991bfee59c927e7c23b1861c6c762e708
("ci : fix arm builds"). It also uses ubuntu-24.04-arm as the runner
which enables us to avoid QEMU.

Resolves: https://github.com/ggml-org/whisper.cpp/issues/2859