Lift Assignment: process lambda assignments in when correctly

So #KT-23346 Fixed

idea/testData/inspectionsLocal/liftOut/ifToAssignment/lambda2.kt

@@ -0,0 +1,10 @@
+fun test(i: Int) {
+    var fn: () -> String
+
+    <caret>if (i == 1)
+        fn = { "foo" }
+    else if (i == 2)
+        fn = { "bar" }
+    else
+        fn = { "baz" }
+}