result of select collation(concat(1,1)); is wrong

[xiongjiwei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

set names utf8mb4 collate utf8mb4_general_ci;
select collation(concat(1,1));
select collation(concat(1 collate `binary`));

2. What did you expect to see? (Required)

utf8mb4_general_ci
binary

3. What did you see instead (Required)

utf8mb4_bin
utf8mb4_bin

this bug was introduced after #19169. but it is not the root cause, since before this PR

select collation(concat(1 collate `binary`));

is wrong too

[liuzix]

/label sig/execution