chore: Add getPageSize() to QueryPaginator (#1987)

* add getPageSize() to QueryPaginator * fix build * fix lint * add javadoc

Author: ron-gal

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/models/Query.java

@@ -407,6 +407,12 @@ public boolean advance(@Nonnull ByteString lastSeenRowKey) {
  query.builder.setRows(remaining);
  return true;
  }
+
+ /** Get the page size of the current Pagniator. For internal use only. */
+ @InternalApi
+ public int getPageSize() {
+ return this.pageSize;
+ }
  }
 
  @Override