Product Types: Remove 'icon' and 'color' from product type fields

[iLLiCiTiT]

Changelog Description

Remove icon and color fields from project.productTypes.

Additional review information

The values of the field is always None and it should not be used anywhere anymore.

Testing notes:

1. Receiving productTypes from project does return only name.

project_name = "..."
project_entity = ayon_api.get_project(project_name, fields={"productTypes"})