feat: update NCCL test passing criteria from 25 to 19

Author: Neelabh94

tools/cloud-build/daily-tests/ansible_playbooks/test-validation/test-gke-a3-high.yml

@@ -60,12 +60,12 @@
   debug:
     msg: "{{nccl_test_logs.stdout}}"
 
-- name: Ensure average bus bandwidth is >= 25 GB/s
+- name: Ensure average bus bandwidth is >= 19 GB/s
   delegate_to: localhost
   ansible.builtin.shell: |
     grep -o '# Avg bus bandwidth    : [0-9\.]*' pod_logs.txt | cut -d ':' -f 2 | awk '{$1=$1;print}'
   register: avg_bus_bandwidth
-  failed_when: avg_bus_bandwidth.stdout | float < 25
+  failed_when: avg_bus_bandwidth.stdout | float < 19
 
 - name: Clean up
   delegate_to: localhost