feat: make permission denied messages optional and configurable

[DevD4v3]

Summary

This PR makes permission denied messages configurable in PlayerCommandServiceOptions.

Changes

• Added PermissionDeniedMessageColor.
• Added PermissionDeniedMessage.
• Allow disabling permission denied messages by setting PermissionDeniedMessage to null.

Motivation

Previously, permission denied responses were hardcoded inside the command service.

This change allows servers to:

• Customize the message text.
• Customize the message color.
• Disable the default message entirely and handle permission feedback through other mechanisms (e.g. GameText and sounds).