CatalogueUI : Suppress imageIndex tool-tip
CatalogueUI : Suppress imageIndex tool-tip

This prevents the `imageIndex` description from appearing as a tool
tip for the entire image listing area.

boberfly/gaffer,johnhaddon/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,boberfly/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,boberfly/gaffer,hradec/gaffer,johnhaddon/gaffer,lucienfostier/gaffer,GafferHQ/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,hradec/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,boberfly/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,hradec/gaffer,GafferHQ/gaffer,hradec/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,hradec/gaffer