KT-31295: fix issue with NewKotlinScriptAction incorrect identity

- this problem leads to the duplication of the `New Kotlin Script` action in the drop-down menu
- ^KT-31295 Fixed

idea/src/org/jetbrains/kotlin/idea/actions/NewKotlinScriptAction.kt

@@ -58,5 +58,5 @@ open class NewKotlinScriptAction(
 
     override fun hashCode(): Int = 0
 
-    override fun equals(other: Any?): Boolean = this::class.isInstance(other)
+    override fun equals(other: Any?): Boolean = this::class == other?.let { it::class }
 }