[ULC] Remove nullability annotation for UL backing fields of private props

compiler/light-classes/src/org/jetbrains/kotlin/asJava/lightClassUtils.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.asJava
 
 import com.intellij.psi.*
+import com.intellij.psi.impl.light.LightField
 import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.asJava.classes.KtLightClass
 import org.jetbrains.kotlin.asJava.classes.KtLightClassForFacade
@@ -241,6 +242,10 @@ fun fastCheckIsNullabilityApplied(lightElement: KtLightElement<*, PsiModifierLis
     // backing fields for lateinit props are skipped
     if (lightElement is KtLightField && annotatedElement is KtProperty && annotatedElement.hasModifier(KtTokens.LATEINIT_KEYWORD)) return false
 
+    if (lightElement is KtLightField && (annotatedElement as? KtModifierListOwner)?.isPrivate() == true) {
+        return false
+    }
+
     if (annotatedElement is KtParameter) {
         val containingClassOrObject = annotatedElement.containingClassOrObject
         if (containingClassOrObject?.isAnnotation() == true) return false