修复 transiton background 示例会相互干扰的问题

(cherry picked from commit 5709ddc6)

pages/CSS/transition/transition.uvue

@@ -78,6 +78,7 @@
         isTransitionStylePadding: false,
         stylePadding: null as UniElement | null,
         isTransitionstyleBackground: false,
+        isTransitionstyleBackground2: false,
         styleBackground: null as UniElement | null,
         styleBackground2: null as UniElement | null,
         isTransitionStyleTransform: false,
@@ -156,11 +157,11 @@
         this.isTransitionstyleBackground = !this.isTransitionstyleBackground
       },
       changeBackground2() {
-        this.styleBackground2?.style?.setProperty("background-color", this.isTransitionstyleBackground
+        this.styleBackground2?.style?.setProperty("background-color", this.isTransitionstyleBackground2
           ? 'brown'
           : 'rgba(0, 0, 0, 0.5);'
         )
-        this.isTransitionstyleBackground = !this.isTransitionstyleBackground
+        this.isTransitionstyleBackground2 = !this.isTransitionstyleBackground2
       },
       propertyChangeBackground() {
         if (!this.isSetTransition) {