Related tdf#111461: ignore picLocks attribute

If we ignore "nvPicPr", we can't take "picLocks" into account
since this tag is used inside "nvPicPr"

It allows to avoid this log:
warn:oox:24274:24274:oox/source/drawingml/shapecontext.cxx:125: ShapeContext::onCreateContext: unhandled element: 3974

Change-Id: Icba7a732f59cf5f3ea587bc23c27cec7a10367c9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92556
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
diff --git a/oox/source/drawingml/shapecontext.cxx b/oox/source/drawingml/shapecontext.cxx
index c6ee29a..b4c284a 100644
--- a/oox/source/drawingml/shapecontext.cxx
+++ b/oox/source/drawingml/shapecontext.cxx
@@ -116,6 +116,7 @@
    case XML_cNvPicPr:
        break;
    case XML_nvPicPr:
    case XML_picLocks:
        break;
    case XML_relIds:
        break;