Update deprecated uses of Zotero.getZoteroDirectory()/getZoteroDatabase()

The Zotero.DataDirectory equivalents return string paths instead of nsIFile
instances, so some of these calls now just use Zotero.File.pathToFile(), which
can be removed when the surrounding code is updated to OS.File,

test/tests/storageLocalTest.js

@@ -157,7 +157,7 @@ describe("Zotero.Sync.Storage.Local", function () {
 			yield OS.File.makeDir(
 				OS.Path.join(dir, 'subdir'),
 				{
-					from: Zotero.getZoteroDirectory().path,
+					from: Zotero.DataDirectory.dir,
 					unixMode: 0o755
 				}
 			);