Add dependency for math edit button

Declare that ext.math.editbutton.enabler depends on
mediawiki.action.edit.

Follow up to: I3d126c1c252c27fa65ab8fb42ffab66a2d99cfa8
Bug: 60471
Change-Id: Ibcda91bbb164b0b896d4c3f5f7c2c6ea6658468e
Merge "Add dependency for math edit button"