优化腾讯云IM block回调兼容swift nullable

TUIKit/TUICore/TUICommonModel.h

@@ -74,7 +74,7 @@ NS_ASSUME_NONNULL_BEGIN
  * Get the cached avatar asynchronously, this interface will request the interface to get the current number of group members, and return the avatar
  * corresponding to the local cache
  */
-+ (void)getCacheGroupAvatar:(NSString *)groupID callback:(void (^)(UIImage *, NSString *groupID))imageCallBack;
++ (void)getCacheGroupAvatar:(NSString *)groupID callback:(void (^)(UIImage * _Nullable, NSString * _Nullable))imageCallBack;
 
 /**
  * Get the cached avatar synchronously, this interface does not request the network

TUIKit/TUICore/TUICommonModel.m

@@ -437,7 +437,7 @@ static void *gScrollViewBoundsChangeNotificationContext = &gScrollViewBoundsChan
     });
 }
 
-+ (void)getCacheGroupAvatar:(NSString *)groupID callback:(void (^)(UIImage *, NSString *groupID))imageCallBack {
++ (void)getCacheGroupAvatar:(NSString *)groupID callback:(void (^)(UIImage * _Nullable image, NSString * _Nullable groupID))imageCallBack {
     if (groupID == nil || groupID.length == 0) {
         if (imageCallBack) {
             imageCallBack(nil, groupID);