Allows easy to use WebImage with isAnimating default to false and change to true later

Since SDAnimatedImage has fallback logic, we can apply this to WebImage by default without dynamic check

Author: dreampiggy

Diff for: Example/SDWebImageSwiftUIDemo/ContentView.swift

@@ -17,6 +17,24 @@ class UserSettings: ObservableObject {
     #endif
 }
 
+struct ContentView5: View {
+    let url: URL = URL(string: "http://assets.sbnation.com/assets/2512203/dogflops.gif")!
+
+    @State private var isAnimating = false
+
+    var body: some View {
+        ZStack {
+            WebImage(url: url, isAnimating: $isAnimating)
+                .pausable(false)
+            Button {
+                isAnimating.toggle()
+            } label: {
+                Text(isAnimating ? "Stop" : "Start")
+            }
+        }
+    }
+}
+
 #if !os(watchOS)
 struct ContentView4: View {
     var url = URL(string: "https://github.com/SDWebImage/SDWebImageSwiftUI/assets/97430818/72d27f90-e9d8-48d7-b144-82ada828a027")!

Diff for: SDWebImageSwiftUI/Classes/WebImage.swift

@@ -132,11 +132,11 @@ public struct WebImage<Content> : View where Content: View {
         if context[.imageScaleFactor] == nil {
             context[.imageScaleFactor] = scale
         }
-        // provide animated image class if the initialized `isAnimating` is true, user can still custom the image class if they want
-        if isAnimating.wrappedValue {
-            if context[.animatedImageClass] == nil {
-                context[.animatedImageClass] = SDAnimatedImage.self
-            }
+        // always provide animated image class to allows dynamic control
+        // since most cases, SDAnimatedImage should be compatible with UIImage
+        // user can still custom the image class if they want
+        if context[.animatedImageClass] == nil {
+            context[.animatedImageClass] = SDAnimatedImage.self
         }
         let imageModel = WebImageModel()
         imageModel.url = url