When `manual_consumption` field on sm is used in any onchange function,
the value will always be computed for the `new_id` record instead of
using the original value stored in database. This results in a different
value in some cases. In this commit, we chech if the compute function is
called from an onchange funtion or not, if so, we use the original value
instead of recomputation.
closesodoo/odoo#140753
Signed-off-by: William Henrotin (whe) <whe@odoo.com>