Do not insert explicit visibility modifier if it's default

idea/testData/intentions/changeVisibility/protected/caretAfter.kt

@@ -0,0 +1,3 @@
+class C {
+    private<caret> fun foo(){}
+}

idea/testData/intentions/changeVisibility/protected/caretAfter.kt.after

@@ -0,0 +1,3 @@
+class C {
+    protected<caret> fun foo(){}
+}

idea/testData/intentions/changeVisibility/protected/overrideVisibilityToDefault.kt.after

@@ -3,5 +3,5 @@ interface I {
 }
 
 abstract class C : I {
-    <caret>protected override fun foo() {}
+    <caret>override fun foo() {}
 }