In order to create the slots table with the correct schema, as it is unused (will be confirmed), it is faster to drop it and then recreate it.
Apply maintenance/archives/patch-slot-origin.sql to all wiki databases (if they already have the slots table). The patch contains the following code:
DROP INDEX /*i*/slot_role_inherited ON /*_*/slots; ALTER TABLE /*_*/slots
DROP COLUMN slot_inherited,
ADD COLUMN slot_origin bigint unsigned NOT NULL; CREATE INDEX /*i*/slot_revision_origin_role ON /*_*/slots (slot_revision_id, slot_origin, slot_role_id);