update theme-change.uvue 修改 this.res.appTheme赋值逻辑

pages/API/theme-change/theme-change.uvue

@@ -80,8 +80,8 @@
       uni.getSystemInfo({
         success: (res:GetSystemInfoResult) => {
           this.osTheme = res.osTheme!
-          this.appTheme = res.appTheme!
-          this.current = this.items.indexOf(this.appTheme)
+          this.appTheme = res.appTheme == "auto" ? res.osTheme! : res.appTheme!
+          this.current = this.items.indexOf(res.appTheme!)
         }
       })
       this.osThemeChangeId = this.bindOsThemeChange()