Before this commit: When o2m inside inner group and it has record then
sometime group is not displayed side by side instead second group comes
below first group.
After this commit: If o2m inside inner group and it has record, it will
always displayed beside first group, the issue was occuring due to
o2m list table layout which is fixed and due to which group width
increased and second group comes below first group, here we are setting
max-width to listview so that it never increase width than max-width.
task-2571376
closesodoo/odoo#72700
Signed-off-by: Simon Genin (ges@odoo) <ges@odoo.com>