Make Sponge's #getFriendlyIdentifier return usernames of Users and display names of Groups (#412)

sponge/sponge-service-api7/src/main/java/me/lucko/luckperms/sponge/service/proxy/api7/SubjectProxy.java

@@ -153,6 +153,11 @@ public class SubjectProxy implements Subject {
         return ref.getSubjectIdentifier();
     }
 
+    @Override
+    public Optional<String> getFriendlyIdentifier() {
+        return getHandle().thenApply(LPSubject::getFriendlyIdentifier).join();
+    }
+
     @Override
     public Set<Context> getActiveContexts() {
         return getHandle().thenApply(handle -> CompatibilityUtil.convertContexts(handle.getActiveContextSet())).join();

sponge/src/main/java/me/lucko/luckperms/sponge/model/SpongeGroup.java

@@ -150,7 +150,8 @@ public class SpongeGroup extends Group {
 
         @Override
         public Optional<String> getFriendlyIdentifier() {
-            return Optional.of(parent.getFriendlyName());
+            String rawDisplayName = parent.getRawDisplayName();
+            return rawDisplayName.equals(getIdentifier()) ? Optional.empty() : Optional.of(rawDisplayName);
         }
 
         @Override

sponge/src/main/java/me/lucko/luckperms/sponge/model/SpongeUser.java

@@ -94,6 +94,11 @@ public class SpongeUser extends User {
             return plugin.getUuidCache().getExternalUUID(parent.getUuid()).toString();
         }
 
+        @Override
+        public Optional<String> getFriendlyIdentifier() {
+            return parent.getName();
+        }
+
         @Override
         public Optional<CommandSource> getCommandSource() {
             final UUID uuid = plugin.getUuidCache().getExternalUUID(parent.getUuid());