Lift Assignment: process lambda assignments in when correctly

So #KT-23346 Fixed

idea/testData/inspectionsLocal/liftOut/ifToAssignment/lambda.kt

@@ -0,0 +1,11 @@
+fun test(i: Int) {
+    var fn: () -> String
+
+    <caret>if (i == 1) {
+        fn = { "foo" }
+    } else if (i == 2) {
+        fn = { "bar" }
+    } else {
+        fn = { "baz" }
+    }
+}