Convert property to function: fix incorrectly conversion when property has explicit generic type

#KT-29192 Fixed

idea/testData/intentions/convertPropertyToFunction/expressionBodyWithGenericType.kt

@@ -0,0 +1,6 @@
+class Test {
+    val <caret>foo: Foo<String>
+        get() = Foo()
+}
+
+class Foo<T>

idea/testData/intentions/convertPropertyToFunction/expressionBodyWithGenericType.kt.after

@@ -0,0 +1,5 @@
+class Test {
+    fun getFoo(): Foo<String> = Foo()
+}
+
+class Foo<T>