Run library processor for server-only projects for Minecraft versions…

… without bundle metadata (#1231)

* run library processor for server-only projects without  bundle metadata

* implement suggested changes

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/MinecraftLibraryProvider.java

@@ -109,12 +109,7 @@ private void provideClientLibraries() {
 
 	private void provideServerLibraries() {
 		final BundleMetadata serverBundleMetadata = minecraftProvider.getServerBundleMetadata();
-
-		if (serverBundleMetadata == null) {
-			return;
-		}
-
-		final List<Library> libraries = MinecraftLibraryHelper.getServerLibraries(serverBundleMetadata);
+		final List<Library> libraries = serverBundleMetadata != null ? MinecraftLibraryHelper.getServerLibraries(serverBundleMetadata) : Collections.emptyList();
 		final List<Library> processLibraries = processLibraries(libraries);
 		processLibraries.forEach(this::applyServerLibrary);
 	}