Introduce Variable: Allow choosing extraction scope for expressions in the lambda body

#KT-7720 Fixed

idea/testData/refactoring/introduceVariable/extractToScope/implicitThisInsideNestedLamba.kt

@@ -0,0 +1,9 @@
+class A(val a: Int)
+class B(val b: Int)
+
+fun foo(f: A.() -> Int) = A(1).f()
+fun bar(f: B.() -> Int) = B(2).f()
+
+fun test() {
+    foo { bar { a + <selection>b</selection> } }
+}