suggest optimize the event of menu on issue/PR sidebar

[a1012112796]

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Description

Hello, I have a suggestions about issue/PR sidebar menu optimize . now when we choose or remove an items on sidebar menu like labels and assignees . it will directly send post event to server. I think it's not necessary, a more good way is just save choices and do ui show. And send the results to server when choose is finished (maybe mean the menu is closed). then we can save same type choics in one comment like github style. Thanks.

[a1012112796]

fixed by #13304