Increase volume size for ARM instance (#39472)

diff --git a/scripts/ci/images/ci_start_arm_instance_and_connect_to_docker.sh b/scripts/ci/images/ci_start_arm_instance_and_connect_to_docker.sh
index 715db56..fb02a9d 100755
--- a/scripts/ci/images/ci_start_arm_instance_and_connect_to_docker.sh
+++ b/scripts/ci/images/ci_start_arm_instance_and_connect_to_docker.sh
@@ -39,6 +39,7 @@
         --region "${REGION}" \
         --image-id "${ARM_AMI}" \
         --count 1 \
+        --block-device-mappings "[{\"DeviceName\":\"/dev/xvda\",\"Ebs\":{\"VolumeSize\":16}}]" \
         --instance-type "${INSTANCE_TYPE}" \
         --user-data "file://${USER_DATA_FILE}" \
         --instance-market-options "${MARKET_OPTIONS}" \