Privilege required to run ALTER INSTANCE RELOAD TLS is too high

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

```sql
% mysql -h 127.0.0.1 -P4000 -u root

mysql> create user 'jack'@'%' identified by 'tidb';
Query OK, 0 rows affected (0.01 sec)

mysql> grant connection_admin on *.* to 'jack'@'%';
Query OK, 0 rows affected (0.01 sec)

mysql> exit

% mysql -h 127.0.0.1 -P4000 -u jack -p

mysql> ALTER INSTANCE RELOAD TLS;
ERROR 1227 (42000): SUPER
mysql> exit

% mysql -h 127.0.0.1 -P4000 -u root

mysql> grant super on *.* to 'jack'@'%';
Query OK, 0 rows affected (0.01 sec)

mysql> exit

% mysql -h 127.0.0.1 -P4000 -u jack -p

mysql> ALTER INSTANCE RELOAD TLS;
Query OK, 0 rows affected (0.58 sec)

mysql> exit
```
### 2. What did you expect to see? (Required)

There is no Tidb document explain what privilege is required to run ALTER INSTANCE RELOAD TLS.

Per mysql document: https://dev.mysql.com/doc/refman/8.0/en/alter-instance.html

> ALTER INSTANCE RELOAD TLS
This action reconfigures a TLS context from the current values of the system variables that define the context. It also updates the status variables that reflect the active context values. This action requires the **CONNECTION_ADMIN** privilege.

### 3. What did you see instead (Required)

But in TiDB, only **CONNECTION_ADMIN** is not enough. **SUPER** is required to run this command.

There are 2 issues here:
1. It is not compatible with mysql.
2. DBA have to grant **SUPER** privilege, give database user to much privileges.

### 4. What is your TiDB version? (Required)

tidb_version(): Release Version: v7.5.0
Edition: Community
Git Commit Hash: 069631e2ecfedc000ffb92c67207bea81380f020
Git Branch: heads/refs/tags/v7.5.0
UTC Build Time: 2023-11-24 08:50:14
GoVersion: go1.21.3
Race Enabled: false
Check Table Before Drop: false
Store: tikv

Start with the ALTER INSTANCE RELOAD TLS privilege check and reproduce the reported SQL sequence using CONNECTION_ADMIN without SUPER. Compare the behavior with the linked MySQL ALTER INSTANCE documentation; done means the command succeeds with CONNECTION_ADMIN alone and coverage verifies that SUPER is not required.

Written by the indexing model from the issue text.