This one is similar to https://github.com/gpac/gpac/issues/1940 

I noticed that the xml dump of file with a `CompactSampleGroupBox` results in invalid xml where `Pattern` tags are never closed.

How to reproduce:

```shell
curl https://conformance.mpeg.expert/ISOBMFF/under_consideration/compact_sample_groups/samplegroups_defrag_compact.mp4 -O
MP4Box -diso samplegroups_defrag_compact.mp4
```

run xml validator on `samplegroups_defrag_compact_info.xml`


Used MP4Box - GPAC version 1.1.0-DEV-rev1632-gf2fddd04-master


btw. is there a way to automate xml validation checks? Could be useful to identify those types of issues when dumping the xml.
ISOBMFF conformance suite issue
This is a GitHub Issue
repo:gpac
owner:gpac
Title : ISOBMFF conformance suite issue
Issue date:

--- start body ---
This one is similar to https://github.com/gpac/gpac/issues/1940 

I noticed that the xml dump of file with a `CompactSampleGroupBox` results in invalid xml where `Pattern` tags are never closed.

How to reproduce:

```shell
curl https://conformance.mpeg.expert/ISOBMFF/under_consideration/compact_sample_groups/samplegroups_defrag_compact.mp4 -O
MP4Box -diso samplegroups_defrag_compact.mp4
```

run xml validator on `samplegroups_defrag_compact_info.xml`


Used MP4Box - GPAC version 1.1.0-DEV-rev1632-gf2fddd04-master


btw. is there a way to automate xml validation checks? Could be useful to identify those types of issues when dumping the xml.
--- end body ---
