Fix group user stub on search.html
Revert "Use 'image' as key, not 'images'". See #12476

This reverts most of commit 81ac72e50e16741b83343c823e522eda7639d452.

Conflicts:
	components/tools/OmeroWeb/omeroweb/webclient/controller/search.py
	components/tools/OmeroWeb/omeroweb/webclient/templates/webclient/search/search.html
Merge pull request #2883 from will-moore/rebased/develop/revert_plugin_breakage_12476

Revert plugin breakage 12476 (rebased onto develop)