[Gradle] Fix friendArtifactResolver for External Targets API

It was failing with ClassCastException in an attempt of using it.

Also added a test case to cover the logic with friendArtifactResolver

^KT-66431 Verification Pending

libraries/tools/kotlin-gradle-plugin-tcs-android/src/main/kotlin/org/jetbrains/kotlin/gradle/android/PrototypeAndroidCompilation.kt

@@ -7,6 +7,7 @@
 
 package org.jetbrains.kotlin.gradle.android
 
+import org.gradle.api.file.ConfigurableFileCollection
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmCompilerOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions
@@ -27,5 +28,7 @@ class PrototypeAndroidCompilation(delegate: Delegate) : DecoratedExternalKotlinC
         get() = super.compilerOptions as HasCompilerOptions<KotlinJvmCompilerOptions>
 
     var androidCompilationSpecificStuff = 10
+
+    val extraFriendPaths: ConfigurableFileCollection = project.files()
 }
 

libraries/tools/kotlin-gradle-plugin-tcs-android/src/main/kotlin/org/jetbrains/kotlin/gradle/android/createAndroidCompilation.kt

@@ -25,6 +25,10 @@ internal fun PrototypeAndroidTarget.createAndroidCompilation(name: String): Prot
         compilationFactory = CompilationFactory(::PrototypeAndroidCompilation)
         compileTaskName = camelCase("prototype", "compile", targetName, name)
 
+        friendArtifactResolver = ExternalKotlinCompilationDescriptor.FriendArtifactResolver { compilation ->
+            compilation.extraFriendPaths
+        }
+
         /*
         Replace Kotlin's compilation association (main <-> test) with noop,
         since Android goes through adding a dependency on the project itself