fix: close modal after leaving queue

[kylehoehns]

Summary

• After clicking "Leave Queue" and confirming, the modal now updates to show a confirmation message with a close button instead of staying open
• Removed the redundant DM notification since the modal already shows the confirmation

Test Plan

• Open queue preferences via the shortcut
• Click "Leave Queue" and confirm
• Modal should update to show confirmation message
• No DM should be sent