fix: clone parquet-testing into `parquet` to match submodule path in verify script (#1617)

`verify-release-candidate.sh` clones the parquet-testing repository into a
`parquet-testing` directory, but the git submodule path declared in
`.gitmodules` is `parquet`, and every parquet-based test reads its data from
`parquet/data/...` (e.g. `python/tests/test_io.py`, `test_store.py`,
`test_context.py`). The arrow-testing clone one line above already correctly
uses the submodule path (`testing`).

This is currently latent because the script's `python3 -m pytest` invocation is
commented out, so the wrong directory is never exercised. Fixing the path is a
prerequisite for enabling the test run during release verification.


Claude-Session: https://claude.ai/code/session_01Pj5DVU7MaammM2nfHh1ZRG

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

dev/release/verify-release-candidate.sh

diff --git a/dev/release/verify-release-candidate.sh b/dev/release/verify-release-candidate.sh
index 503e0de..42e3970 100755
--- a/dev/release/verify-release-candidate.sh
+++ b/dev/release/verify-release-candidate.sh
@@ -132,7 +132,7 @@
 
   # Clone testing repositories into the expected location
   git clone https://github.com/apache/arrow-testing.git testing
-  git clone https://github.com/apache/parquet-testing.git parquet-testing
+  git clone https://github.com/apache/parquet-testing.git parquet
 
   python3 -m venv .venv
   if [ -x ".venv/bin/python" ]; then