fix: add second order by shortUrl when searching for links

[halfwhole]

Problem

Bulk-created links with the same createdAt time are not necessarily returned in the same order when sorting links by createdAt only. This may cause issues, like the sort order of bulk links suddenly changing when one of the links is updated

See Notion issue - [Create] Link sort order seems to be changed after adding the tag and Notion issue - [Create] [Update] Link status changes after adding or updating the tag

Solution

Add a second ORDER BY condition on shortUrl, leading to a deterministic ordering with bulk-created links

• Possible drawback is that the search could take extra time: shortUrl doesn't seem to be an indexed field (but then again, we're currently ordering by createdAt which doesn't seem to be indexed either)
• But locally at least, searching with 20k links is still super fast