RedundantLetInspection: fix false negative for references

#KT-34603 Fixed

idea/testData/inspectionsLocal/simpleRedundantLet/reference.kt

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+val a = 42.let<caret> { t -> t }.also { println(it) }

idea/testData/inspectionsLocal/simpleRedundantLet/reference.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+val a = 42.also { println(it) }

idea/testData/inspectionsLocal/simpleRedundantLet/reference2.kt

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+val a = 42.let<caret> { it }

idea/testData/inspectionsLocal/simpleRedundantLet/reference2.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+val a = 42

idea/testData/inspectionsLocal/simpleRedundantLet/reference3.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun Int.foo() {
+    let<caret> { it }
+}

idea/testData/inspectionsLocal/simpleRedundantLet/reference3.kt.after

@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+
+fun Int.foo() {
+}

idea/testData/inspectionsLocal/simpleRedundantLet/reference4.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun Int.foo() {
+    let<caret> { it }.also(::println)
+}

idea/testData/inspectionsLocal/simpleRedundantLet/reference4.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun Int.foo() {
+    also(::println)
+}