[FIX] mass_mailing: text style dropup should be visible

Before this commit:

Text style and text size drop-up were not fully visible due to overflow.

After this commit:

Added a scroll property to give accessibility to the items.

Task- 3100123

closes odoo/odoo#110547

X-original-commit: dbe410fdc93b1eb89d70c9b2a51e81b0075147d4
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

addons/mass_mailing/static/src/scss/mass_mailing.ui.scss

@@ -347,5 +347,14 @@ body.editor_enable.o_basic_theme.o_in_iframe {
     }
     #oe_snippets.o_loaded {
         transform: translateX(0);
+
+        > .o_we_customize_panel .oe-toolbar {
+            #style.dropup, #font-size.dropup {
+                > .dropdown-menu {
+                    overflow-y: scroll;
+                    max-height: 200px;
+                }
+            }
+        }
     }
 }