"Remove redundant '.let' call" intention: handle it inside function call

So #KT-20583 Fixed

idea/testData/intentions/replaceSingleLineLetIntention/functionCallOnSafeCall.kt

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo(s: String, i: Int) = s.length + i
+
+fun test() {
+    val nullable: String? = null
+    nullable?.let<caret> { foo(it, 1) }
+}