fix: allow falsy secret values

[carloitaben]

I'm setting some secrets in my project and I need some placeholder values to be falsy values. For example, when using a db file with SQLite for local development with Drizzle and Turso I want to set the secrets this way:

new sst.Secret("TursoDatabaseUrl", "file:local.db")
new sst.Secret("TursoDatabaseAuthToken", "")

In order to do this

import { Resource } from "sst"
import type { Config } from "drizzle-kit"

export default {
  // ...
  dbCredentials: {
    url: Resource.TursoDatabaseUrl,
    authToken: Resource.TursoDatabaseAuthToken,
  },
} satisfies Config

I'm sure there's a safer way to do this, just trying to kick off the discussion with this PR 🙂

[jayair]

@thdxr take a look?