[fix] CLinkshell::ChangeMemberRank crash

[sruon]

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• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

When promoting a linkpearl to a sack, the original linkpearl is destroyed and then accessed by the subsequent query which causes the map server to crash inconditionally.

Line was removed in #7322

Steps to test these changes

• Give pearl to 2nd char
• Promote pearl to sack
• No crash