Remove references to validateTaskProperties

The task is now called `validatePlugins`.

libraries/tools/kotlin-gradle-plugin/build.gradle.kts

@@ -152,7 +152,7 @@ tasks {
     }
 
     named("install") {
-        dependsOn(named("validateTaskProperties"))
+        dependsOn(named("validatePlugins"))
     }
 
     named<DokkaTask>("dokka") {
@@ -163,7 +163,7 @@ tasks {
 
 projectTest {
     executable = "${rootProject.extra["JDK_18"]!!}/bin/java"
-    dependsOn(tasks.named("validateTaskProperties"))
+    dependsOn(tasks.named("validatePlugins"))
 
     workingDir = rootDir
 }