Use arm runner on arm kernel builds

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>

Author: jacobweinstock

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
             mainline_runner: '{"group":"Default","labels":["oracle-vm-16cpu-64gb-x86-64"]}'
           - arch: arm64
             fork_runner: ubuntu-24.04-arm
-            mainline_runner: '{"group":"Default","labels":["oracle-vm-16cpu-64gb-x86-64"]}'
+            mainline_runner: '{"group":"Default","labels":["oracle-vm-16cpu-64gb-arm64"]}'
     env:
       ARCH: ${{ matrix.arch }}
       KERNEL_MODE: docker