[FIX] web: fix studio child view datapoint content

Issue

    - Install Employees & Studio
    - Configuration > Check Skills Management
    - Go on an employee form
    - Remove all data in Experience, Education & Skills
    - Open Studio
    - Click in the blank space before Skills
    - Edit Form View

    Traceback

Cause

    The ORM tries to get the parent fields because the generated
    datapoint includes them. (45bc7c92)

    Normally the parent model is the same than the child model
    but not in studio.

Solution

    Merging the fields in the datapoint only if the models are the same.

OPW-2125214

closes odoo/odoo#41317

Related: odoo/enterprise#7179
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>