avoid modifying serversCache serverList from multithreading

Bug: app force close during updating subscribe

Reroduce steps: quickly scroll up and down the RecyclerView during updating subscribe
if the server list length is more than the screen height, the bug can be 100% reproduced

Solution: reloadServerList from UI Thread

Signed-off-by: zhaoguomanong <zhaoguomanong@gmail.com>

V2rayNG/app/src/main/kotlin/com/v2ray/ang/viewmodel/MainViewModel.kt

@@ -54,13 +54,9 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
 
     fun reloadServerList() {
         serverList = MmkvManager.decodeServerList()
-        viewModelScope.launch(Dispatchers.Default) {
         updateCache()
-            launch(Dispatchers.Main) {
         updateListAction.value = -1
     }
-        }
-    }
 
     fun removeServer(guid: String) {
         serverList.remove(guid)