fix(sveltekit): rename `adapter.ts` -> `adapters.ts` in `@auth/sveltekit` (#12503)
rename adapter.ts -> adapters.ts in framework-sveltekit
The package.json exports ./adapters, consistent with other
packages. This meant it was not accessible for consumption
when the source file and exported files didn't match.
Co-authored-by: Thang Vu <hi@thvu.dev>