fix some Xerces-C++ memory leaks

Back-porting from !34516 (merged) plus adding a missing release in GeoModelXml.

GeoModelXml still reports many leaks, but this seems to remove a subset of them - the rest still need to be pinned down.

This merge request affects 2 packages:

• DetectorDescription/AGDD/AGDDControl
• DetectorDescription/GeoModelXml

Affected files list will not be printed in this case

Adding @rosati ,@wleight ,@nkoehler ,@rbianchi as watchers

added 21.9 Geometry review-pending-level-1 labels

CI Result SUCCESS (hash 5f446a6a)

	Athena
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 107
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 24798]

Looks fine to me. Warnings are not related to this MR. Approving. Cheers, L1

added review-approved label and removed review-pending-level-1 label

mentioned in commit 944e814f

merged

added sweep:ignore label