[mysql] Duplicate subsegments when using `createPool().query`

When using connection pools, the `pool.query` method can be called directly as a shortcut instead of calling `pool.getConnection`, then querying ([doc](https://github.com/mysqljs/mysql?tab=readme-ov-file#pooling-connections)):

> [pool.query] is a shortcut for the pool.getConnection() -> connection.query() -> connection.release() code flow.

As a result, the subsegments for that query are duplicated because both `pool.query` and `pool.getConnection().query` have been captured to create subsegments, and both are called.

Here's an example:

``` javascript
const AWSXRay = require('aws-xray-sdk')

AWSXRay.captureMySQL(require('mysql2'))
const mysqlPromise = require('mysql2/promise')

const ns = AWSXRay.getNamespace()

async function testPromisePoolQuery() {
try {
const pool = mysqlPromise.createPool({
host: 'localhost',
user: 'user',
password: 'password',
database: 'test',
connectionLimit: 10,
queueLimit: 0,
})

await pool.query('SELECT 1')

await pool.end()
} catch (err) {
console.error('Error connecting to database:', err)
}
}

ns.run(async () => {
let segment = new AWSXRay.Segment('testPromisePoolQuery')

AWSXRay.setSegment(segment)
await testPromisePoolQuery()
console.log(
`testPromisePoolQuery # of subsegments: ${AWSXRay.getSegment().subsegments?.length}`
)
segment.close()
})
```

The result printed from this is `testPromisePoolQuery # of subsegments: 2`, and if you view the subsegment you can see that the queries are the same, and timings are almost exactly the same.