Switch from x86 to ARM build host for POWER8+ builds. (#19575)

* Switch from x86 to ARM build host for POWER8+ builds.

This should improve build times at least a little bit.

* Include distro config in Docker CI skip check.

It should have been added previously, but got missed.

.github/data/distros.yml

@@ -40,7 +40,7 @@ arch_data:  # Mapping of per-architecture matrix behavior.
   aarch64: *arm64
   ppc64le:
     qemu: true
-    runner: ubuntu-24.04
+    runner: ubuntu-24.04-arm
 static_arches:  # Static build architectures
   - x86_64
   - armv6l

.github/workflows/docker.yml

@@ -70,6 +70,7 @@ jobs:
             .dockerignore
             CMakeLists.txt
             netdata-installer.sh
+            .github/data/distros.yml
             .github/workflows/docker.yml
             .github/scripts/docker-test.sh
             .github/scripts/gen-matrix-docker.py