Ignores not being applied for Cargo

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Package ecosystem

cargo

### Package manager version

cargo 1.67.1

### Language version

Rust 1.67.1

### Manifest location and content before the Dependabot update

https://github.com/apache/arrow-ballista-python/blob/main/Cargo.toml

### dependabot.yml content

https://github.com/apache/arrow-ballista-python/blob/main/.github/dependabot.yml

### Updated dependency

datafusion 18.0.0 -> 19.0.0

### What you expected to see, versus what you actually saw

It should have been ignored.

### Native package manager behavior

_No response_

### Images of the diff or a link to the PR, issue, or logs

_No response_

### Smallest manifest that reproduces the issue

_No response_

Start by reviewing the referenced Cargo.toml and .github/dependabot.yml files to identify the dependency and ignore rule. Then trace the Cargo update handling in dependabot-core and reproduce the datafusion 18.0.0 to 19.0.0 update. Done means the configured ignore is honored and a regression test covers this case.

Written by the indexing model from the issue text.