LPS-39594 Update the last publish date only after the whole publication process succeeded not right after export
LPS-39594 Whereever we call the updateLastPublishDate from outside the scope of Staging/StagingImpl it used for setting the last publish date and not clearing. The method could be misused and accidentally clearing the date causing collosion in staging. Removing clear code part to make it more robust and easy to call from the outside.
LPS-39594 Within the StagingImpl scope a proctected method we used to use the updateLastPublishDate for clearing the last publish date as well. Because this is an internal usage within the StagingImpl scope creating a new protected method to clear the las publish date preventing misuse of the update method which is public
LPS-39594 Perform the same refactoring for portlet level last-publish-date
LPS-39594 Moving back update call to LayoutExporter - here we only have this call once, not from three different places