GLTF: Fix document loader error code path

assigned to @mwestphal

@michael.migliore please review

Warnings:

• please consider adding a changelog entry in a file ending with .md in Documentation/release/dev.

The warnings do not need to be fixed, but it is recommended to do so.

Do: test -s quick

+2

Do: test

dashboard is clean, merging

Do: merge

mentioned in commit 9549e62f

merged manually

mentioned in merge request !11264 (merged)

mentioned in commit mwestphal/paraview@b25632ad

mentioned in merge request paraview/paraview!6912 (merged)

mentioned in commit mwestphal/paraview@65a86150

mentioned in commit mwestphal/paraview@1b44b9a4

mentioned in commit mwestphal/paraview@433100ec