FunctionWithLambdaExpressionBodyInspection: fix ClassCastException for "Remove braces" quick fix

#KT-32580 Fixed

idea/testData/inspectionsLocal/functionWithLambdaExpressionBody/removeBraces/kt32580.kt

@@ -0,0 +1,6 @@
+// FIX: Remove braces
+class C {
+    fun f4() = {<caret>
+        "single-expression function which returns lambda"
+    }
+}

idea/testData/inspectionsLocal/functionWithLambdaExpressionBody/removeBraces/kt32580.kt.after

@@ -0,0 +1,4 @@
+// FIX: Remove braces
+class C {
+    fun f4() = "single-expression function which returns lambda"
+}

idea/testData/inspectionsLocal/functionWithLambdaExpressionBody/wrapRun/kt32580.kt

@@ -0,0 +1,7 @@
+// FIX: Convert to run { ... }
+// WITH_RUNTIME
+class C {
+    fun f4() = {<caret>
+        "single-expression function which returns lambda"
+    }
+}

idea/testData/inspectionsLocal/functionWithLambdaExpressionBody/wrapRun/kt32580.kt.after

@@ -0,0 +1,5 @@
+// FIX: Convert to run { ... }
+// WITH_RUNTIME
+class C {
+    fun f4() = run { "single-expression function which returns lambda" }
+}