[WIP] Fix IllegalStateException on Play.Server.BUNDLE with MONITOR listener

[Copilot]

• Review the prior PR change and current comment feedback
• Run existing targeted checks to understand the current baseline
• Rework the BUNDLE/MONITOR handling with the smallest possible code change
• Run targeted tests for the touched area
• Run code review and security scan
• Reply on the PR comment with the addressing commit hash

Original prompt

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This section details on the original issue you should resolve

<issue_title>IllegalStateException on Play.Server.BUNDLE with MONITOR listener: ProtocolLib attempts to cancel read-only PacketEvent</issue_title>
<issue_description>- [x] This issue is not solved in a development build

Describe the bug
When a plugin registers a ProtocolLib sending listener on PacketType.Play.Server.BUNDLE with ListenerPriority.MONITOR, ProtocolLib throws IllegalStateException: The packet event is read-only. during outbound processing.

To Reproduce
Steps to reproduce the behavior:

1. Register a PacketAdapter for sending with ListenerPriority.MONITOR and include PacketType.Play.Server.BUNDLE in the whitelist (or use PacketType.values()).
2. Trigger normal gameplay actions that cause bundled outbound packets. (In my case, just cancel the PlayerItemConsumeEvent)

Expected behavior
ProtocolLib should not attempt to cancel a read-only event, or should avoid this MONITOR/read-only conflict in the internal BUNDLE handling path.

Version Info
https://just-paste.it/Qk2807a7dp

Additional context
Code: https://just-paste.it/Nx2il2q2ri
</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes IllegalStateException on Play.Server.BUNDLE with MONITOR listener: ProtocolLib attempts to cancel read-only PacketEvent #3603

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[dmulloy2]

@copilot try again