[SPARK-35463][BUILD][FOLLOWUP] Redirect output for skipping checksum …

…check

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

This patch is a followup of SPARK-35463. In SPARK-35463, we output a message to stdout and now we redirect it to stderr.

### Why are the changes needed?

All `echo` statements in `build/mvn` should redirect to stderr if it is not followed by `exit`. It is because we use `build/mvn` to get stdout output by other scripts. If we don't redirect it, we can get invalid output, e.g. got "Skipping checksum because shasum is not installed." as `commons-cli` version.

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

No. Dev only.

### How was this patch tested?

Manually test on internal system.

Closes apache#32637 from viirya/fix-build.

Authored-by: Liang-Chi Hsieh <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>
(cherry picked from commit 594ffd2)
Signed-off-by: Dongjoon Hyun <[email protected]>

build/mvn

@@ -85,7 +85,7 @@ install_app() {
         fi
       fi
     else
-      echo "Skipping checksum because shasum is not installed."
+      echo "Skipping checksum because shasum is not installed." 1>&2
     fi
 
     cd "${_DIR}" && tar -xzf "${local_tarball}"