Add when branches: include auto-import

Before this commit, enum / sealed class to add was not imported so
user had to import them himself. Now everything is auto-imported.
Separate "add with import" is kept but * import is now in mind there.
#KT-22330 Fixed
#KT-22354 Fixed
EA-108090 Fixed

idea/testData/quickfix/when/addRemainingBranchesAnotherPackage.before.Main.kt

@@ -0,0 +1,10 @@
+// "Add remaining branches" "true"
+
+package u
+
+import e.getOwnEnum
+
+fun mainContext() {
+    val ownLocal = getOwnEnum()
+    <caret>when (ownLocal) {}
+}