[FIX] discuss: channel name overflow

Before this commit:
The channel name used to overflow in the channel suggestion section.

After this commit:
The name will not overflow in the channnel suggestion section.

Task id: 3366608

closes odoo/odoo#126910

X-original-commit: 138275d1
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>