Product Collection - incorrect default number of products in editor when inheriting query

[kmanijak]

Description

By default when blocks inherit from query templates, there's a difference in number of displayed products:

Steps to reproduce

1. Go to Editor and edit Product Catalog template
2. Insert Product Collection and Products (Beta) blocks
3. Make sure both of them have "Inherit query from template" options enabled
4. Save the template
5. Check number of products displayed in editor and frontend for both blocks:

x	Products (Beta)	Product Collection
Editor	10	9
Frontend	12	12

Expected outcome

Template query is controlled externally, hence we should adjust to that. If it displays 12 products, both Products (Beta) and Product Collection block should display this amount in Editor as well, so:

• when "Inherit query from template" option is enabled items per page should be 12.
• otherwise, it should be 9 by default.