ci(labeler): drop path-based T-dependencies rule

[DaleSeo]

Motivation and Context

This PR removes the T-dependencies rule from the PR labeler. The labeler adds T-dependencies to any PR that touches a Cargo.toml. But most PRs edit Cargo.toml for other reasons: [[test]] targets, features, or dev-dependencies. Dependabot already adds T-dependencies to its cargo PRs, so the labeler rule only adds noise. A narrower glob would not help.

Breaking Changes

None.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[github-actions]

@bolinfest is on triage rotation this week and is the reviewer for this one.

Labels come from the PR labeler. Please review the change.

_{Automated triage. Labels are a first pass and the assigned maintainer has the final say.}