bug-fix: Fixed a bug where operator list and muted members list not being updated (#943)

Fixes: [CLNP-2099](https://sendbird.atlassian.net/browse/CLNP-2099)

### Changelogs
- Fixed a bug where muted member list is not being updated after a
member had been unmuted
- Fixed a bug where operator list is not being updated after an operator
had been removed


[CLNP-2099]:
https://sendbird.atlassian.net/browse/CLNP-2099?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: chohongm

src/modules/ChannelSettings/components/ModerationPanel/MutedMemberList.tsx

@@ -99,7 +99,12 @@ export const MutedMemberList = (): ReactElement => {
                       <MenuItem
                         onClick={() => {
                           channel?.unmuteUser(member).then(() => {
-                            refreshList();
+                            /**
+                             * Limitation to server-side table update delay.
+                             */
+                            setTimeout(() => {
+                              refreshList();
+                            }, 500);
                             closeDropdown();
                           });
                         }}

src/modules/ChannelSettings/components/ModerationPanel/OperatorList.tsx

@@ -100,9 +100,7 @@ export const OperatorList = (): ReactElement => {
                       <MenuItem
                         onClick={() => {
                           channel?.removeOperators([operator.userId]).then(() => {
-                            setOperators(operators.filter(({ userId }) => (
-                              userId !== operator.userId
-                            )));
+                            refreshList();
                           });
                           closeDropdown();
                         }}
@@ -157,7 +155,12 @@ export const OperatorList = (): ReactElement => {
           <AddOperatorsModal
             onCancel={() => setShowAdd(false)}
             onSubmit={() => {
-              refreshList();
+              /**
+               * Limitation to server-side table update delay.
+               */
+              setTimeout(() => {
+                refreshList();
+              }, 500);
               setShowAdd(false);
             }}
           />