Fix readAccess in IDELightClassGenerationSupport on obtaining script

#EA-211576 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/IDELightClassGenerationSupport.kt

@@ -43,6 +43,7 @@ import org.jetbrains.kotlin.idea.caches.lightClasses.LazyLightClassDataHolder
 import org.jetbrains.kotlin.idea.project.languageVersionSettings
 import org.jetbrains.kotlin.idea.resolve.frontendService
 import org.jetbrains.kotlin.idea.stubindex.KotlinTypeAliasShortNameIndex
+import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -139,14 +140,15 @@ class IDELightClassGenerationSupport(private val project: Project) : LightClassG
     }
 
     override fun createUltraLightClass(element: KtClassOrObject): KtUltraLightClass? {
+        return runReadAction {
             if (element.shouldNotBeVisibleAsLightClass() ||
                 element is KtEnumEntry ||
                 element.containingKtFile.isScript()
             ) {
-            return null
+                return@runReadAction null
             }
 
-        return KtUltraLightSupportImpl(element).let { support ->
+            KtUltraLightSupportImpl(element).let { support ->
                 when {
                     element is KtObjectDeclaration && element.isObjectLiteral() ->
                         KtUltraLightClassForAnonymousDeclaration(element, support)
@@ -161,6 +163,7 @@ class IDELightClassGenerationSupport(private val project: Project) : LightClassG
                 }
             }
         }
+    }
 
     private fun KtFile.hasAlias(shortName: Name?): Boolean {
         if (shortName == null) return false