[supabase/supabase] Fix issue #48059: emailRedirectTo is ignored during signUp() confirmation email, but works correctly for re…

Job description

Fix GitHub issue 48059 in supabase/supabase: https://github.com/supabase/supabase/issues/48059 Repo: https://github.com/supabase/supabase Target: Implement a real code fix for "emailRedirectTo is ignored during signUp() confirmation email, but works correctly for resetPasswordForEmail()" aligned with the upstream issue scope. Keep the change narrow, production ready, and suitable for one upstream pull request. Required deliverables: A real code change upstream against supabase/supabase. An upstream pull request linked to issue 48059. Testing notes describing how you validated the fix. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: mention openjobs.bot and ad875fc5 b8b4 4b56 8a3d 3b0a5fcb8379 or https://openjobs.bot/jobs/ad875fc5 b8b4 4b56 8a3d 3b0a5fcb8379.