K2: use lookupTag instead of classId in use-site scopes

We used this classId to get an associated symbol,
but this way is anyway not recommended (e.g. problems with local classes).
In this commit we migrated to usage of lookup tags instead.

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirReferenceShortener.kt

@@ -617,7 +617,7 @@ private class ElementsToShortenCollector(
     private fun FirScope.correspondingClassIdIfExists(): ClassId = when (this) {
         is FirNestedClassifierScope -> klass.classId
         is FirNestedClassifierScopeWithSubstitution -> originalScope.correspondingClassIdIfExists()
-        is FirClassUseSiteMemberScope -> classId
+        is FirClassUseSiteMemberScope -> ownerClassLookupTag.classId
         else -> errorWithAttachment("FirScope ${this::class}` is expected to be one of FirNestedClassifierScope and FirClassUseSiteMemberScope to get ClassId") {
             withEntry("firScope", this@correspondingClassIdIfExists) { it.toString() }
         }