[Gradle] Kotlin2JsCompile: convert enhancedFreeCompilerArgs to ArrayList

... using .toList():
Using ListProperty.get() can return List implementations
that do not play well with CompilerArguments.
In this particular case RegularImmutableList from guava was returned
which later failed in the copyBeanTo function

^KT-58427 Verification Pending

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/Kotlin2JsCompile.kt

@@ -167,7 +167,7 @@ abstract class Kotlin2JsCompile @Inject constructor(
 
             // Overriding freeArgs from compilerOptions with enhanced one + additional one set on execution phase
             // containing additional arguments based on the js compilation configuration
-            args.freeArgs = executionTimeFreeCompilerArgs ?: enhancedFreeCompilerArgs.get()
+            args.freeArgs = executionTimeFreeCompilerArgs ?: enhancedFreeCompilerArgs.get().toList()
         }
 
         pluginClasspath { args ->