feat(eckhart): Add new Back Header message type

core/embed/rust/src/ui/layout_eckhart/component/header.rs

@@ -84,6 +84,7 @@ pub struct Header {
 
 #[derive(Copy, Clone)]
 pub enum HeaderMsg {
+    Back,
     Cancelled,
     Menu,
 }

core/embed/rust/src/ui/layout_eckhart/component/text_screen.rs

@@ -105,6 +105,7 @@ where
             match msg {
                 HeaderMsg::Cancelled => return Some(TextScreenMsg::Cancelled),
                 HeaderMsg::Menu => return Some(TextScreenMsg::Menu),
+                _ => {}
             }
         }
         if let Some(msg) = self.action_bar.event(ctx, event) {