[FIX] project: fix the portal chatter button's visibility

Before this commit, Chatter in project sharing: the
'employees only' and 'visible' buttons are not toggled and both
are visible at same time.

So in this commit fixes the issue by making the 'employee only'
and 'visible' button as toggle button same as portal chatter.

task-2858336

closes odoo/odoo#99326

X-original-commit: eee722bb74db70a49ba88250afd0359c510e5ade
Signed-off-by: Laurent Stukkens (ltu) <ltu@odoo.com>

addons/project/static/src/scss/project_sharing/chatter.scss

@@ -26,6 +26,18 @@
             width: 45px;
             height: 45px;
         }
+
+        .o_portal_message_internal_off {
+            .btn-danger {
+                display: none;
+            }
+        }
+
+        .o_portal_message_internal_on {
+            .btn-success {
+                display: none;
+            }
+        }
     }
 
     &.o-aside {