signals: Rebuild stale global cache entries automatically (#4809)

* signals: Rebuild stale global cache entries automatically

* remove log

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/signals/src/global/mod.rs

@@ -182,12 +182,20 @@ where
         let context = get_global_context();
 
         // Get the entry if it already exists
+        let mut evicted_stale_entry = false;
         {
             let read = context.map.borrow();
             if let Some(signal) = read.get(&key) {
-                return signal.downcast_ref::<T>().cloned().unwrap();
+                if let Some(signal) = signal.downcast_ref::<T>() {
+                    return signal.clone();
+                }
+                evicted_stale_entry = true;
             }
         }
+
+        if evicted_stale_entry {
+            context.map.borrow_mut().remove(&key);
+        }
         // Otherwise, create it
         // Constructors are always run in the root scope
         let signal = dioxus_core::Runtime::current().in_scope(ScopeId::ROOT, || {