Port Gleam 1.3 JS fixes to Nix

[PgBiel]

Ports the following JS target fixes to Nix:

1. Adds bit array byte-alignment compile-time checks (Try to compile time error when trying to make non byte aligned array on js gleam-lang/gleam#3111)
2. Do not unnecessarily rewrite gleam.nix in the build output (from the fix to gleam build generates gleam.mjs and gleam.d.mts even if they already exist gleam-lang/gleam#3178 at gleam-lang/gleam@9755365)
3. Fix using aliased record constructors in constants (from the fix for Imports renamed with as then used in consts generate invalid JavaScript code gleam-lang/gleam#3294 at gleam-lang/gleam@ec614e7)

Also added a test to verify that gleam-lang/gleam#3379 does not apply to the Nix target.