chore(PostgrestBuilder): dynamic import `@supabase/node-fetch`

[liyachun01]

Dynamic import('@supabase/node-fetch') in PostgresBuilder to avoid possible Cannot read property 'bind' of undefined error.

Closes #574

[liyachun01]

Hi @soedirgo, please kindly look at this PR, thanks~

[mandarini]

I will be closing this issue, since we will be removing @supabase/node-fetch by the end of October 2025. If you think that this change is still needed, please open a new PR in our new repository, here: https://github.com/supabase/supabase-js

Thank you very much for your contribution. 💚 Our community makes Supabase better every day!