Add missed license headers (#10478)

src/main/java/net/minecraftforge/common/extensions/IForgeLevelSummary.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.common.extensions;
 
 import net.minecraft.world.level.storage.LevelSummary;

src/test/java/net/minecraftforge/debug/resource/ResourceLocationTest.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.debug.resource;
 
 import net.minecraft.gametest.framework.GameTest;