Convert permissions to lowercase inside the cache

Slight optimization, toLowerCase is a relatively expensive call in the scheme of permission checks.

api/src/main/java/me/lucko/luckperms/api/context/ContextManager.java

@@ -47,6 +47,8 @@ import java.util.Optional;
  * <li>{@code org.bukkit.entity.Player}</li>
  * <li>{@code net.md_5.bungee.api.connection.ProxiedPlayer}</li>
  * <li>{@code org.spongepowered.api.service.permission.Subject}</li>
+ * <li>{@code cn.nukkit.Player}</li>
+ * <li>{@code com.velocitypowered.api.proxy.Player}</li>
  * </ul>
  *
  * @since 4.0

common/src/main/java/me/lucko/luckperms/common/calculator/PermissionCalculator.java

@@ -81,10 +81,6 @@ public class PermissionCalculator implements Function<String, Tristate> {
      * @return the result
      */
     public Tristate getPermissionValue(String permission, PermissionCheckEvent.Origin origin) {
-        // convert the permission to lowercase, as all values in the backing map are also lowercase.
-        // this allows fast case insensitive lookups
-        permission = permission.toLowerCase();
-
         // get the result
         Tristate result = this.lookupCache.get(permission);
 
@@ -97,6 +93,10 @@ public class PermissionCalculator implements Function<String, Tristate> {
 
     @Override
     public Tristate apply(@NonNull String permission) {
+        // convert the permission to lowercase, as all values in the backing map are also lowercase.
+        // this allows fast case insensitive lookups
+        permission = permission.toLowerCase();
+
         // offer the permission to the permission vault
         // we only need to do this once per permission, so it doesn't matter
         // that this call is behind the cache.