[FIR] Stop report OptIn usage error for delegate fields

This change preserves the old behaviour

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt

diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt
index 73ceb23..3c1748f 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt
@@ -134,6 +134,9 @@
         dispatchReceiverType: ConeKotlinType?,
     ): Set<Experimentality> {
         ensureResolved(FirResolvePhase.STATUS)
+        if (this.fir is FirDelegateField) {
+            return emptySet()
+        }
         val fir = this.fir
         if (!visited.add(fir)) return emptySet()
         val result = knownExperimentalities ?: SmartSet.create()