[StorageStats] support apps uninstalled with DELETE_KEEP_DATA

codePath can be null for apps uninstalled with DELETE_KEEP_DATA. The
downstream code would crash if there's a null inside the codePaths
array passed into Installer.getAppSize.

Also makes sure that the correct storageUuid and data dir is preserved
in the PackageInfo query result.

BUG: 288142708
Test: manually tested with test code and verified it doesn't crash
Test: to be added in cts
Change-Id: If7cb1c3cba7a66994780a65c7aa3884889e16c65