fixed PY-6835 Convert lambda to function: leads to syntactically incorrect code when lambda expression is the only statement in function

python/testData/intentions/afterConvertLambdaToFunction2.py

@@ -0,0 +1,5 @@
+def transform():
+  def function(x):
+      return x + 5
+
+  return function

python/testData/intentions/beforeConvertLambdaToFunction2.py

@@ -0,0 +1,2 @@
+def transform():
+  return lambda <caret>x: x + 5