Fix nested State update issue (#538)

Author: Kyle-Ye

Sources/OpenSwiftUICore/Data/State/StoredLocation.swift

@@ -35,7 +35,7 @@ package class StoredLocationBase<Value>: AnyLocation<Value>, Location, @unchecke
                 return false
             }
             box.$data.access { data in
-                _ = data.savedValue.removeFirst()
+                _ = data.savedValue.removeLast()
             }
             return true
         }

Tests/OpenSwiftUICompatibilityTests/Data/State/StateCompatibilityTests.swift

@@ -5,6 +5,7 @@
 import Testing
 import OpenSwiftUITestsSupport
 
+@MainActor
 struct StateCompatibilityTests {
     @Test
     func appear() async throws {
@@ -32,4 +33,41 @@ struct StateCompatibilityTests {
             )
         }
     }
+
+    @Test("StoredLocationBase.BeginUpdate.removeLast verify")
+    func nestedStateUpdate() async throws {
+        @MainActor
+        enum Helper {
+            static var values: [Int] = []
+            static var valueChanges: [[Int]] = []
+        }
+
+        struct ContentView: View {
+            @State private var value = 0
+
+            var body: some View {
+                let _ = Helper.values.append(value)
+                Color.white
+                    .onAppear {
+                        value = 1
+                        value = 2
+                        withAnimation {
+                            value = 3
+                            value = 4
+                        }
+                    }
+                    .onChange(of: value) { oldValue, newValue in
+                        Helper.valueChanges.append([oldValue, newValue])
+                    }
+            }
+        }
+
+        try await triggerLayoutWithWindow(expectedCount: 0) { _ in
+            PlatformHostingController(
+                rootView: ContentView()
+            )
+        }
+        #expect(Helper.values == [0, 2, 4])
+        #expect(Helper.valueChanges == [[0, 2], [2, 4]])
+    }
 }