### What this PR does / why we need it?
Disable per-PR triggering for A3 for now, we trigger the dist test in
the label `dist-test` rather than
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
- vLLM version: v0.10.1.1
- vLLM main:
136d853e65
Signed-off-by: wangli <wangli858794774@gmail.com>