Indicate to users that query names need to be unique for query building

[fzhao99]

Description:

Slack thread for context: https://skylight-hq.slack.com/archives/C05BEG226RZ/p1733786682798469

We decided that query names in query building should be unique. Will need designs for whatever copy/error states we want to add to indicate to users we have this constraint.

Acceptance Criteria:

GIVEN a user is going to add a new query via query building

WHEN the enter a new query name

THEN it should be clear that they need a unique name

GIVEN a user inputs a duplicate query name

WHEN they try to save that query

THEN error states appear to redirect them accordingly

[linear]

QUE-110 Indicate to users that query names need to be unique for query building