[FW][FIX] mail: allow bypassing message attachments check

[fw-bot]

We only care about data fields when it comes to restricting access to message attachments.
As some modules may use these attachments directly, it may be desirable for them to use
the attachment name or similar metadata fields.

"write" is only restricted if writing on a data field, as it's effectively the same as unlinking
for our purposes. Other fields have the same access rights as prior to [1]

Additional changes:

• Admins can delete attachments from message in the UI again
• Check returns True instead of None when it succeeds, to match its parent
• AccessError is raised with a cause so that we can detect if it was raised because of the message check

1: 4c4e63f

task-3519815

Forward-Port-Of: #165158
Forward-Port-Of: #164894

[robodoo]

Pull request status dashboard.

[fw-bot]

@reth-odoo @awa-odoo cherrypicking of pull request #164894 failed.

stdout:

Auto-merging addons/mail/i18n/mail.pot
CONFLICT (content): Merge conflict in addons/mail/i18n/mail.pot
Auto-merging addons/mail/models/ir_attachment.py
CONFLICT (content): Merge conflict in addons/mail/models/ir_attachment.py
CONFLICT (modify/delete): addons/test_mail/tests/test_ir_attachment.py deleted in HEAD and modified in a8e88749f18d ([FIX] mail: add exceptions to message attachment checks).  Version a8e88749f18d ([FIX] mail: add exceptions to message attachment checks) of addons/test_mail/tests/test_ir_attachment.py left in tree.

stderr:

15:29:59.329317 git.c:463               trace: built-in: git cherry-pick a8e88749f18d00a7f2321b5d083befcbe7265d20
error: could not apply a8e88749f18d... [FIX] mail: add exceptions to message attachment checks
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
----------
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.

⚠️ after resolving this conflict, you will need to merge it via @robodoo.

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

[reth-odoo]

@robodoo r+