[MINOR] Ensure structured_logging_style runs out of correct directory

### What changes were proposed in this pull request?

Currently, `structured_logging_style.py` assumes that it's being run from the `dev` directory. If it's run from the project root, it will scan all files in the parent directory, i.e. outside the project root. I encountered this and was surprised that it was taking minutes just in the globbing step.

This change avoids that assumption, so `python dev/structured_logging_style.py` will still produce correct results.

### Why are the changes needed?

Make it easier for developers to run the structured logging checks locally.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

```
dev/structured_logging_style.py
```

### Was this patch authored or co-authored using generative AI tooling?

No

Closes apache#51087 from sryza/structured-logging-dir.

Authored-by: Sandy Ryza <sandy.ryza@databricks.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

Author: sryza

dev/structured_logging_style.py

@@ -41,7 +41,7 @@ def main():
 
     nonmigrated_files = {}
 
-    scala_files = glob.glob(os.path.join("../", "**", "*.scala"), recursive=True)
+    scala_files = glob.glob(os.path.join(__file__, "../", "**", "*.scala"), recursive=True)
 
     for file in scala_files:
         skip_file = False