Additional fix for the lb.CopyFiles workflow task to treat new cloud-store path semantics correctly.

Fix for case when copying part of an alpha-tree leaf page to a sibling empty one fails due to unfortunate caching/encoding.

This release contains changes to some lb-workflow tasks related to workbook creation. These fixes have not been applied yet to lb.wb.CreateWorkbook, which means errors related to recent changes in the LB runtime that imposes restrictions on string lengths can still occur. Please note that this known issue does apply to lb.wb.util.CreateWorkbook.