[bug] Command sender should be player when using Player::performCommand

[wu-vincent]

Describe the bug
When a plugin uses Player::performCommand to run a plugin command, the command executor is called with a generic CommandSender object instead of Player. This is due to the current implementation of Player::performCommand using VirtualCommandOrigin to execute the command, which is not correctly converted to Player upon callback.

To Reproduce

1. Add a new plugin command
2. Call Player::performCommand to run that plugin command
3. Check the type of sender in onCommand callback.

Expected behavior
The type of sender should be Player.