Fix clicked UI nodes getting reset when hovering child nodes (#4194)

# Objective

Fixes #4193

## Solution

When resetting a node's `Interaction` to `None`, ignore any `Clicked` node because that should be handled by the mouse release check exclusively.

crates/bevy_ui/src/focus.rs

@@ -169,7 +169,8 @@ pub fn ui_focus_system(
     // reset lower nodes to None
     for (_entity, _focus_policy, interaction, _) in moused_over_z_sorted_nodes {
         if let Some(mut interaction) = interaction {
-            if *interaction != Interaction::None {
+            // don't reset clicked nodes because they're handled separately
+            if *interaction != Interaction::Clicked && *interaction != Interaction::None {
                 *interaction = Interaction::None;
             }
         }