cargo build: Silence s3tables warning

[def-]

Seen locally during cargo build --all:

warning: Patch iceberg-catalog-s3tables v0.7.0 (https://github.com/MaterializeInc/iceberg-rust.git?rev=cf1e6e0c9de3#cf1e6e0c) was not used in the crate graph.
Check that the patched package version and available features are compatible with the dependency requirements. If the patch has a different version from what is locked in the Cargo.lock file, run cargo update to use the new version. This may also occur with an optional dependency that is not enabled.

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).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[DAlperin]

we can temporarily remove this patch for now, it is legit unused in the current main. will fix in #34431