EditProject by member: saving description does not work in some cases

A new project, shared by multiple users, with empty field "Max Operation size".

Enter the project details page with a project member (not the admin). The user can change the description, and press Save, but the changes are not preserved (we remain on the same page), because an error message is thrown related to "Max Operation size" being empty.

We should allow empty "Max Operation size", or missing from **data dictionary.