Without ci.sourcegraph.bazelrc the bazel environment won't have the right credentials to access the db. This adds the rc to the bazel-do invocation.

For context - the ci.sourcegraph.bazelrc contains this following

# Needed for DB in CI
common --test_env=PGUSER=postgres
common --test_env=PGPASSWORD=postgres
common --test_env=PGSSLMODE=disable
common --test_env=PGDATABASE=postgres

Test plan

https://buildkite.com/sourcegraph/sourcegraph/builds/280332#01905ef3-1fce-4d76-bf5b-0530dc434cff

Changelog

• sg - ensure bazel-do invocations use the ci sourcegraph bazelrc