point to sa-submission-q2-2026 branch instead

[biswapanda]

Point to sa-submission-q2-2026 with DP health check fix

---

Note

Low Risk
Single-line branch pin for one benchmark matrix path; no auth, data, or application logic changes.

Overview
For dynamo-vllm multinode runs of minimaxm3 at fp8 on the B300 launcher, the srt-slurm clone now checks out sa-submission-q2-2026 instead of main.

That matches the default branch used for other B300 srt-slurm jobs in the same script and pulls in the DP health check fix described for this submission branch.

^{Reviewed by Cursor Bugbot for commit fa925b9. Bugbot is set up for automated code reviews on this repo. Configure here.}