Make the JNI API to get list offsets as a view public. (#10807)

This is an API I would like to use to help a customer with a UDF so I would like to make it public.

Authors:
  - Robert (Bobby) Evans (https://github.com/revans2)

Approvers:
  - Jason Lowe (https://github.com/jlowe)

URL: #10807

java/src/main/java/ai/rapids/cudf/ColumnView.java

@@ -233,8 +233,10 @@ public final ColumnView getChildColumnView(int childIndex) {
 
   /**
    * Get a ColumnView that is the offsets for this list.
+   * Please note that it is the responsibility of the caller to close this view, and the parent
+   * column must out live this view.
    */
-  ColumnView getListOffsetsView() {
+  public ColumnView getListOffsetsView() {
     assert(getType().equals(DType.LIST));
     return new ColumnView(getListOffsetCvPointer(viewHandle));
   }