Infrastructure: Preserve more sync table type information (#239)

In supporting StructuredQueries 0.22 we began relying on some
underscored APIs. Let's instead prefer public, documented APIs wherever
possible.

Author: stephencelis

Sources/SQLiteData/CloudKit/CloudKitSharing.swift

@@ -104,7 +104,7 @@
             """
         )
       }
-      guard !privateTables.contains(where: { T.self == $0 })
+      guard !privateTables.contains(where: { T.self == $0.base })
       else {
         throw SharingError(
           recordTableName: T.tableName,