[FW][FIX] account_cashbox: add cashbox_id to unique session constraint

[fw-bot-adhoc]

Forward-Port-Of: #481

[roboadhoc]

Pull request status dashboard.

[fw-bot-adhoc]

@cav-adhoc @jjscarafia cherrypicking of pull request #481 failed.

stdout:

Auto-merging account_cashbox/models/account_cashbox_session.py
Auto-merging account_cashbox/__manifest__.py
CONFLICT (content): Merge conflict in account_cashbox/__manifest__.py

stderr:

14:06:59.114509 git.c:444               trace: built-in: git cherry-pick 461f364f2d94e0dbac1da9f8ebd0845b054f5d83
error: could not apply 461f364f... [FIX] account_cashbox: add cashbox_id to unique session constraint
hint: after resolving the conflicts, mark the corrected paths
hint: with 'git add <paths>' or 'git rm <paths>'
hint: and commit the result with 'git commit'
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status:

Either perform the forward-port manually (and push to this branch, proceeding as usual) or close this PR (maybe?).

In the former case, you may want to edit this PR message as well.

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