Bug 1951016: Blocks not being turned off on gridstack pages

When a blocktype is set to hidden (inactive) on the plugins page then
instances of the blocktype should not show on pages anymore unless we
are in versioning mode

Change-Id: I9901e18cc84a102227f4e75b57d0d84f838c6644
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit d9177ea4)