Keep TaskProviders out of the unit-test task's onlyIf spec for configuration-cache compatibility

The configuration cache serializes the AGP unit-test task's whole
state, including its onlyIf specs. The render wiring's onlyIf captured
the Wired records, whose RoboSpec/anchor fields hold TaskProviders —
realized DefaultTasks — so storing the entry failed with:

  Task `:app:testDebugUnitTest` of type
  `com.android.build.gradle.tasks.factory.AndroidUnitTest`: cannot
  serialize object of type 'org.gradle.api.DefaultTask', a subtype of
  'org.gradle.api.Task', as these are not supported with the
  configuration cache.

and every generateNavGraph/export run needed --no-configuration-cache.

Materialize the render-list Files before configuring the test task and
let the spec capture only those — plain Files serialize fine. The
sysprops were already eager strings; no behavior change.

Fixes #1

Author: pesjak

compose-nav-graph-gradle/src/main/kotlin/com/github/skydoves/navgraph/gradle/NavGraphGradlePlugin.kt

@@ -708,6 +708,10 @@ public class NavGraphGradlePlugin : Plugin<Project> {
       gradle.taskGraph.whenReady {
         val active = wired.filter { hasTask(it.anchor.get()) }
         if (active.isEmpty()) return@whenReady
+        // Materialized OUTSIDE the closures attached to the test task: the configuration cache serializes that
+        // task's whole state — sysprops AND its onlyIf specs — so a spec capturing `active` would drag each
+        // Wired's TaskProviders (realized DefaultTasks) into the entry and fail serialization. Plain Files don't.
+        val renderListFiles = active.map { it.renderListFile.get().asFile }
         agpTest.get().apply {
           filter {
             includeTestsMatching("*NavGraphRobolectricRenderTest")
@@ -723,9 +727,7 @@ public class NavGraphGradlePlugin : Plugin<Project> {
           }
           // Run iff ANY active pipeline has a non-empty render list (a Layoutlib failure to fill somewhere).
           onlyIf {
-            active.any { w ->
-              w.renderListFile.get().asFile.let { it.isFile && it.readText().isNotBlank() }
-            }
+            renderListFiles.any { it.isFile && it.readText().isNotBlank() }
           }
           // Force the render to run when requested (the prior thumbnails aren't a tracked output of the test).
           outputs.upToDateWhen { false }