[MINOR][BUILD] Correct the files contend in checkstyle-suppressions.xml

### What changes were proposed in this pull request?
The pr aims to change the suppress files from `sql/core/src/main/java/org/apache/spark/sql/api.java/*` to `sql/core/src/main/java/org/apache/spark/sql/api/java/*`, the former seems to be a wrong code path.

### Why are the changes needed?
Correct the `files` contend in `checkstyle-suppressions.xml`

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
Pass GitHub Actions

Closes apache#38469 from LuciferYang/fix-java-supperessions.

Authored-by: yangjie01 <[email protected]>
Signed-off-by: Sean Owen <[email protected]>
(cherry picked from commit 5457193)
Signed-off-by: Sean Owen <[email protected]>

Author: LuciferYang

dev/checkstyle-suppressions.xml

@@ -33,7 +33,7 @@
     <suppress checks=".*"
               files="external/spark-ganglia-lgpl/src/main/java/com/codahale/metrics/ganglia/GangliaReporter.java"/>
     <suppress checks=".*"
-              files="sql/core/src/main/java/org/apache/spark/sql/api.java/*"/>
+              files="sql/core/src/main/java/org/apache/spark/sql/api/java/*"/>
     <suppress checks="LineLength"
               files="src/test/java/org/apache/spark/sql/hive/test/Complex.java"/>
     <suppress checks="LineLength"