ORC-2152: Upgrade Maven to 3.9.15

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

This PR aims to upgrade Maven to 3.9.15.

### Why are the changes needed?

To bring the latest bug fixes.
- https://maven.apache.org/docs/3.9.15/release-notes.html

### How was this patch tested?

Pass the CIs.

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

Generated-by: Claude Opus 4.7 (1M context)

Closes #2605 from dongjoon-hyun/ORC-2152.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

Author: dongjoon-hyun

java/pom.xml

@@ -82,7 +82,7 @@
     <maven.compiler.proc>full</maven.compiler.proc>
     <maven.compiler.release>${java.version}</maven.compiler.release>
     <maven.compiler.useIncrementalCompilation>false</maven.compiler.useIncrementalCompilation>
-    <maven.version>3.9.14</maven.version>
+    <maven.version>3.9.15</maven.version>
 
     <mockito.version>5.23.0</mockito.version>
     <orc-format.version>1.1.1</orc-format.version>