Fix injection on vanilla (or any official-mapping client)

Author: Candicey

loader/src/main/kotlin/net/weavemc/loader/impl/InjectionHandler.kt

@@ -84,7 +84,7 @@ public object InjectionHandler : SafeTransformer {
 
             nsOrder.windowed(2).forEach { (last, curr) ->
                 node.remap(last, curr)
-                groupedModifiers.getValue(curr).forEach { it.apply(node, hookConfig) }
+                groupedModifiers[curr]?.forEach { it.apply(node, hookConfig) }
             }
 
             val classWriter = InjectionClassWriter(hookConfig.classWriterFlags, classReader)

loader/src/main/kotlin/net/weavemc/loader/impl/bootstrap/transformer/ApplicationWrapper.kt

@@ -98,8 +98,8 @@ public object ApplicationWrapper {
         }
     }
 
-    private class WrappingLoader : URLClassLoader(emptyArray(), getSystemClassLoader()) {
-        override fun loadClass(name: String, resolve: Boolean) =
+    public class WrappingLoader : URLClassLoader(emptyArray(), getSystemClassLoader()) {
+        override fun loadClass(name: String, resolve: Boolean): Class<*> =
             findClass(name).also { if (resolve) resolveClass(it) }
 
         override fun findClass(name: String): Class<*> {