fix problematic doctest

from redis docs for ACL DELUSER:
Delete all the specified ACL users and terminate all the connections
 that are authenticated with such users

Nodejs complains: Warning: Detected unsettled top-level await
which in turn gives the error code 13 in the workflow

await client.auth({ username: 'test-user' ...});
// deleting the user that is currently logged in -> bad
await client.sendCommand(['ACL', 'DELUSER', 'test-user']);
await client.quit()

fix: authenticate with the default user before deleting the test-user

Author: nkaradzhov

doctests/cmds-cnxmgmt.js

@@ -39,6 +39,7 @@ console.log(res3); // OK
 
 // REMOVE_START
 assert.equal(res3, "OK");
+await client.auth({ username: 'default', password: '' })
 await client.sendCommand(['ACL', 'DELUSER', 'test-user']);
 // REMOVE_END
 // STEP_END