[Gradle, JS] Add test on css and migrate one test on groovy dsl

#KT-32721 fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-browser-project/app/build.gradle.kts

@@ -5,6 +5,7 @@ plugins {
 dependencies {
     implementation(kotlin("stdlib-js"))
     implementation(project(":lib"))
+    implementation(npm(projectDir.resolve("src/main/css")))
 }
 
 kotlin {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-browser-project/app/src/main/css/main.css

@@ -0,0 +1,3 @@
+body {
+    background-color: aliceblue;
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-browser-project/app/src/main/kotlin/App.kt

@@ -6,5 +6,8 @@
 package com.example
 
 fun main() {
+    require("css/main.css")
     println("Sheldon: ${sheldon()}")
-}
+}
+
+external fun require(o: String)

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-nodejs-project/build.gradle

@@ -1,9 +1,9 @@
 plugins {
-    kotlin("js").version("<pluginMarkerVersion>")
+    id("org.jetbrains.kotlin.js") version "<pluginMarkerVersion>"
 }
 
 dependencies {
-    implementation(kotlin("stdlib-js"))
+    implementation("org.jetbrains.kotlin:kotlin-stdlib-js")
 }
 
 repositories {