Permissions of offline player cannnot be removed correctly

[siulung201314]

Description

Permissions of offline player cannnot be removed correctly.

Expected Behavior

Permissions of offline player should be removed correctly.

Steps to Reproduce

1. Set the tier permission in tiers.yml
   tier 1 permission = example.perm.here
   tier 2 permission = exmaple.perm2.here
   tier 3 permission = exmaple.perm3.here
   tier 4 permission = exmaple.perm4.here
   tier 5 permission = exmaple.perm5.here
   tier 6 permission = exmaple.perm6.here
2. Restart the server
3. Create a guild
4. Use command /guild admin addplayer to add an offline player
5. Use command /guild admin upgrade to upgrade the guild
6. Restart the server
7. Use command /guild admin upgrade to upgrade the guild again 4 times.
8. Check the permission of the offline player
9. The lower tier permssion of the offline player is still here and is not removed correctly.

Your Environment

• Guilds version 3.5.6.7-SNAPSHOT
• MC Version Purpur-1814 (MC: 1.19.2)
• Plugin List CMI, CMILib, Guilds, LuckPerms, PlaceholderAPI, Guilds, Vault