Fix SAM conversion when lambda is the last expression of another lambda

#KT-39691 Fixed

compiler/testData/diagnostics/tests/samConversions/conversionOnLambdaAsLastExpression.kt

@@ -0,0 +1,20 @@
+// FIR_IDENTICAL
+
+// FILE: C.java
+
+public interface C { void on(String s); }
+
+// FILE: A.java
+
+public class A { void add(C c) {} }
+
+// FILE: test.kt
+
+class B : A() {
+    fun test(x: Any?) {
+        add(foo { { _ : String -> Unit } })
+        add(x?.let { { _ : String -> Unit } })
+    }
+}
+
+fun <T> foo(f: () -> T): T = f()

compiler/testData/diagnostics/tests/samConversions/conversionOnLambdaAsLastExpression.txt

@@ -0,0 +1,27 @@
+package
+
+public fun </*0*/ T> foo(/*0*/ f: () -> T): T
+
+public open class A {
+    public constructor A()
+    public/*package*/ open fun add(/*0*/ c: C!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B : A {
+    public constructor B()
+    public/*package*/ open override /*1*/ /*fake_override*/ fun add(/*0*/ c: C!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final fun test(/*0*/ x: kotlin.Any?): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface C {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public abstract fun on(/*0*/ s: kotlin.String!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}