Verification script should pull test repos with `git submodule`

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
An issue came up while building a release candidate for 59.0.0 (#9110). The current verification script pulls test data directly from their respective repos
https://github.com/apache/arrow-rs/blob/9f96a8f5c3f47c6303c7d17ac7f00ad4ad0df513/dev/release/verify-release-candidate.sh#L114-L116

This caused verification to fail because a new file was recently added to parquet-testing/bad_data, which caused the arrow_reader/bad_data test to fail (it checks for new files that haven't yet had tests added).

**Describe the solution you'd like**
To avoid this issue in the future, I think it would be better for the script to instead invoke `git submodule update --init` to pull the testing data.

Start at dev/release/verify-release-candidate.sh around lines 114-116 and inspect how the test repositories are currently pulled. Check the repository's submodule configuration, then update the verification step to use git submodule update --init. Run the release-candidate verification flow and confirm it uses the pinned test data without picking up unrelated new files.

Written by the indexing model from the issue text.