Update Azure Linux arm64 image (#20835)

Author: marcpopMSFT

eng/pipelines/templates/variables/vmr-build.yml

@@ -55,6 +55,6 @@ variables:
   - name: poolImage_Linux
     value: build.ubuntu.2204.amd64
   - name: poolImage_LinuxArm64
-    value: Azure-Linux-3-Arm64
+    value: build.azurelinux.3.arm64
   - name: poolName_LinuxArm64
     value: Docker-Linux-Arm-Internal