fix: use frontend instead of generated (#21860) (#22326) (#22335)

Co-authored-by: Teppo Kurki <teppo.kurki@vaadin.com>

Author: vaadin-bot

flow-plugins/flow-gradle-plugin/src/main/kotlin/com/vaadin/gradle/VaadinBuildFrontendTask.kt

@@ -85,7 +85,7 @@ public abstract class VaadinBuildFrontendTask : DefaultTask() {
         check(tokenFile.exists()) { "token file $tokenFile doesn't exist!" }
 
         val options = Options(null, adapter.get().classFinder, config.npmFolder.get())
-            .withFrontendDirectory(BuildFrontendUtil.getGeneratedFrontendDirectory(adapter.get()))
+            .withFrontendDirectory(BuildFrontendUtil.getFrontendDirectory(adapter.get()))
             .withFrontendGeneratedFolder(config.generatedTsFolder.get())
         val cleanTask = TaskCleanFrontendFiles(options)
 
@@ -135,7 +135,7 @@ public abstract class VaadinBuildFrontendTask : DefaultTask() {
      * @return `true` to remove created files, `false` to keep the files
      */
     protected open fun cleanFrontendFiles(): Boolean {
-        if (FrontendUtils.isHillaUsed(BuildFrontendUtil.getGeneratedFrontendDirectory(adapter.get()),
+        if (FrontendUtils.isHillaUsed(BuildFrontendUtil.getFrontendDirectory(adapter.get()),
                         adapter.get().classFinder)) {
             /*
              * Override this to not clean generated frontend files after the