Fix broken error handling in v2_ratelimit_limit handler

[Flo4604]

Error handling in go/apps/api/routes/v2_ratelimit_limit/handler.go at line 167 is broken.

The handler tries to find a row that only exists in the current transaction (Tx), which results in an error with "no rows found" when executed.

Investigate and correct the error handling logic so that it does not attempt to look up rows that are only present in the transaction context.

[linear]

ENG-2285