make PR to add fragment unblock to official xray-core

[AliM1988]

Integrity requirements

• I confirm that I have read the documentation, understand the meaning of all the configuration items I wrote, and did not pile up seemingly useful options or default values.
• I searched issues and did not find any similar issues.

Version

v1.8.13-mahsa-r2

Description

Please make PR on official repository to add fragment unblock to official xray-core.

Reproduction Method

Nothing

Client config

Server config

.

Client log

Server log