Inter-schema relationship suggestions do not load properly in the console

I have upgraded to Hasura `v2.0.0-alpha.6` locally to check that we won't have problems when Hasura Cloud upgrades us.

When adding a new table, I found that the Hasura Console would no longer suggest object/array relationships - a pretty major regression!

After further investigation, I found that the problem is actually a bit more subtle:

* If you only have foreign keys pointing to tables in the same schema, the suggestions appear just fine
* If you only have foreign keys pointing to tables outside the schema, the suggestions *never* appear
* If you have a mixture of foreign keys pointing inside and outside the schema, the internal suggestions will appear when you first open the *Relationships* tab. Then, if you switch away to another tab and return, the rest of the suggestions will appear.