DocsUI to support other intent action for file picking

In RootsFragment, we refactored the logic of sorting and adding
personal/work header from includeHandlerApps to one layer up
(sortLoadResult). This allows us to also apply those to just
providers, rather than providers and apps previously.

Bug: 142925443
Bug: 149771504
Test: manual - save file from PrintActivity, local/cross profile
Test: manual - check the returned tree uri attached userInfo
Test: manual - check the returned uri from open_document
Test: atest DocumentsUIGoogleTests

Change-Id: I94d805de1b560eff1257b803a6d452599f9088d2