FIR2IR: enhance approximation of captured types

compiler/testData/ir/irText/expressions/sam/genericSamProjectedOut.fir.kt.txt

@@ -2,13 +2,13 @@ fun test(a: SomeJavaClass<out String>) {
   a.someFunction(hello = local fun <anonymous>(it: String?) {
     return Unit
   }
- /*-> Hello<Any?>? */)
+ /*-> Hello<String>? */)
   a.plus(hello = local fun <anonymous>(it: String?) {
     return Unit
   }
- /*-> Hello<Any?>? */)
+ /*-> Hello<String>? */)
   a.get(hello = local fun <anonymous>(it: String?) {
     return Unit
   }
- /*-> Hello<Any?>? */)
+ /*-> Hello<String>? */)
 }