[Bug] - REST responses return empty tags

[lrm25]

Describe the bug
REST responses directly from s3 do not return empty tags, but REST responses from versitygw do. While not a serious issue, optional XML tags that aren't set shouldn't be returned.

For example, versitygw returns this when there is no object lock config rule:

<?xml version="1.0" encoding="UTF-8"?>
<ObjectLockConfiguration><ObjectLockEnabled>Enabled</ObjectLockEnabled><Rule></Rule></ObjectLockConfiguration>

s3 returns this:

<?xml version="1.0" encoding="UTF-8"?>
<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>Enabled</ObjectLockEnabled></ObjectLockConfiguration>

Since Rule is an optional parameter and isn't set.

To Reproduce

1. Send a "GET" rest command, e.g. versioning: https://github.com/versity/versitygw/blob/test_cmdline_rest_retention/tests/rest_scripts/get_bucket_versioning.sh
2. Send for both direct (s3.amazonaws.com) and versitygw.
3. Compare the two. Note the empty tags after sending to versitygw.

Expected behavior
versitygw doesn't return unnecessary optional XML tags.

Server Version
Version : v1.0.7
Build : b7291c3
BuildTime: 2024-09-25_08:28:23PM
Darwin Lukes-MacBook-Pro.local 23.4.0 Darwin Kernel Version 23.4.0: Fri Mar 15 00:12:25 PDT 2024; root:xnu-10063.101.17~1/RELEASE_ARM64_T6030 arm64

[mlt180]

This issue has been fixed in this PR