[FIX] mail: make composer use same subtype as message replied to

Before this commit, when clicking on reply in inbox would send a message
whatever the subtype of message the reply is linked to.
This commit makes sure that if the message which we want to reply to
is a note (resp. comment), then the reply will be a note (resp. comment)

task-2282363

closes odoo/odoo#54158

X-original-commit: 27956951eebc7c068a7d57e8bd21c29522f3ff9e
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>