Adjust mobileWebEditing to fit anon editing

Anonymous users don't have an edit count, so wgUserEditCount will
be null (which is not a valid type for this property). Use 0 instead.

Bug: 71252
Change-Id: Ie1c9dab3051590afffb7ed68c98bb9e595480479
Merge "Adjust mobileWebEditing to fit anon editing"