[FIX] condominium: prevent error when opening form view of motion

[fw-bot]

When a user opens the form view of a motion, a traceback will appear.

Steps to reproduce the error:

• Install the condominium module
• Go to Calendar > Create a new meeting > Set Condominium >
  In the Motions Tab, Set a Voting key and Motion > Save
• Click on the View button of the motion

Traceback:

ZeroDivisionError: float division by zero

industry/condominium/data/ir_model_fields.xml

Lines 876 to 877 in 5af6517

	x_in_favor = sum(attendee.x_ratio for attendee in event.attendee_ids if (attendee.x_delegating or attendee.x_attending) and attendee.partner_id.id in voters)
	record['x_in_favor'] = x_in_favor / sum([x_ratio.x_ratio for x_ratio in event.x_voting_key_id.x_ratio_ids]) / event.x_attending_ratio

The error occurs because the computation divides by:
sum([x_ratio.x_ratio for x_ratio in event.x_voting_key_id.x_ratio_ids])

This value can become 0 when:

• There are no x_ratio_ids, or
• The sum of x_ratio values equals 0

As a result, the division raises a ZeroDivisionError when opening the motion form view.

sentry-7317501911

Forward-Port-Of: #1822

[robodoo]

[fw-bot]

This PR targets saas-19.1 and is part of the forward-port chain. Further PRs will be created up to master.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port