[FIX] partner_autocomplete: field as title is too short

Before this commit when the partner autocomplete field was used
the form title css rules defined in o_field_char were missing.

So now the width: 100% is also applied when the partner autocomplete
is a title and takes the whole available space.

closes odoo#114580

Signed-off-by: Pierre Paridans (app) <app@odoo.com>

addons/partner_autocomplete/static/src/scss/partner_autocomplete.scss

@@ -30,3 +30,8 @@
         }
     }
 }
+
+// Same rule as .oe_title .o_field_char
+.o_form_view .o_form_editable .oe_title .o_field_field_partner_autocomplete {
+    width: 100%;
+}