fix(go): process URI before other options to avoid nondeterminism

[ewgenius]

Problem

When BigQueryDatabaseInit is called with both a uri and explicit auth options (e.g. adbc.bigquery.sql.auth_type, adbc.bigquery.sql.auth_credentials), the connection intermittently fails with:

Could not create client: bigquery: constructing client: credentials: could not find default credentials

The failure is non-deterministic - the same set of options may succeed on one call and fail on the next.

Root cause: databaseImpl.SetOptions iterates a map[string]string, which has non-deterministic order in Go. "uri" is the only macro key in the options set - ParseBigQueryURIToParams expands it into multiple fields and unconditionally sets auth_type = ADC when the URI contains no OAuthType query parameter (e.g. a plain bigquery:///project-id). All other keys are simple independent field writes. When the map iteration happened to visit "uri" after the explicit auth options, the URI parser silently overwrote the caller's auth_type back to ADC. newClient() then skipped the provided credentials entirely and fell through to Application Default Credentials discovery.

Solution

Fix SetOptions to always process "uri" first, before iterating the rest of the options. Since "uri" is the only key with expansion side-effects, this single ordering guarantee is sufficient - all other keys are independent field writes and their relative order does not matter.

ParseBigQueryURIToParams is unchanged: a URI without OAuthType still correctly defaults to ADC for callers who provide only a URI with no explicit auth options.

[lidavidm]

Good catch, thank you!

[github-actions]

✔️ Test passed: spiceai/bigquery@22ea9bc
Workflow run: https://github.com/adbc-drivers/bigquery/actions/runs/23518311247

[lidavidm]

GitHub seems to be broken, despite the all-green status page...

[lidavidm]

GitHub still won't let me merge this. @ewgenius do you mind re-creating the PR?

[ewgenius]

@lidavidm sure, I'll recreate

[ewgenius]

@lidavidm I've created new one #143