CatalogueUI : Select correct image after deletion
CatalogueUI : Select correct image after deletion

If the metadata index was 0 from a drag to the top, then we'd ignore
it and select the preceding plug index's row.

Fixes #3554.

Fixes
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 - Catalogue : Fixed bug when deleting an image that had been dragged to
   the top, that resulted in incorrect image selection after deletion (#3554).

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