[FIR] Update return type of delegated callables in ReturnTypeCalculator

^KT-54654 Fixed

compiler/testData/codegen/box/delegation/kt54654.kt

@@ -0,0 +1,22 @@
+// TARGET_BACKEND: JVM_IR
+// ISSUE: KT-54654
+
+fun accessProperty(b: B) = b.property
+fun accessFunction(b: B) = b.function()
+
+fun getString_1(): String = "O"
+fun getString_2(): String = "K"
+
+interface A {
+    val property get() = getString_1()
+    fun function() = getString_2()
+}
+
+class B(val a: A) : A by a
+
+class C : A
+
+fun box(): String {
+    val b = B(C())
+    return accessProperty(b) + accessFunction(b)
+}