The error occurs when we validate the quality worksheet template.

Steps to reproduce:
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- Install the ``quality_mrp_workorder_worksheet`` module
- Quality > Configuration > Quality Worksheet Templates
- Click on ``Design Template``
- Click on ``Close``
- Click on ``Validate``

Traceback:
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``ValueError: Expected singleton : quality.check()``

This error occurs at [1], where we are receiving ``self`` as empty.

Previous behavior:
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When we try to design a template in the ``Quality Worksheet Templates`` the studio opens as expected. However, if we close it without making any changes, we are redirected to the form view. In this view, we encounter strange behavior and are unable to perform any actions.

After behavior:
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Now, when we click on ``Design Template`` from the list view and then close it, we are redirected to the form view of the ``Quality Worksheet Templates``.

[1]- https://github.com/odoo/enterprise/blob/7eb1131b413afc2549382d2524ec83445803b682/quality_mrp_workorder_worksheet/models/quality.py#L12

sentry-5695518176