fix(alert): made it easier to tell if alert is scrollable in MD mode (#23976)

Author: averyjohnston

core/src/components/alert/alert.md.vars.scss

@@ -80,7 +80,7 @@ $alert-md-message-empty-padding-bottom:       $alert-md-message-empty-padding-to
 $alert-md-message-empty-padding-start:        $alert-md-message-empty-padding-end !default;
 
 /// @prop - Maximum height of the alert content
-$alert-md-content-max-height:                 240px !default;
+$alert-md-content-max-height:                 266px !default;
 
 /// @prop - Border width of the alert input
 $alert-md-input-border-width:                 1px !default;