tests: Disable sanity restart in 0dt test

[def-]

Seen failing in
https://buildkite.com/materialize/nightly/builds/8260#01905bf7-5892-4aa4-bad3-720e1cd51b68 with "halting process: this deployment has been fenced out"

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• This PR includes the following user-facing behavior changes:

[benesch]

Thanks!