Update expiry notification to use the copy token link

[0xPoe]

ref #8717

Tested locally:

1. Start the crates.io in the docker

crates.io on  rustin-patch-copy-token via 🐳 orbstack is 📦 v0.0.0 via  v20.13.0 via 🦀 v1.81.0-nightly took 2s 
❯ docker ps
CONTAINER ID   IMAGE               COMMAND                  CREATED          STATUS             PORTS                                       NAMES
7ce772c8b3b2   cratesio-worker     "cargo run --bin bac…"   4 minutes ago    Up 4 minutes                                                   cratesio-worker-1
5047a4401dfe   cratesio-frontend   "pnpm start"             10 minutes ago   Up 10 minutes      0.0.0.0:4200->4200/tcp, :::4200->4200/tcp   cratesio-frontend-1
e740cac267e7   cratesio-backend    "/app/docker_entrypo…"   10 minutes ago   Up 10 minutes      0.0.0.0:8888->8888/tcp, :::8888->8888/tcp   cratesio-backend-1
f7d983f426bb   postgres:16         "docker-entrypoint.s…"   12 days ago      Up About an hour   127.0.0.1:5432->5432/tcp                    cratesio-postgres-1

2. Create a new token which will expire within one day

3. Trigger a background job: DATABASE_URL=postgresql://postgres:password@localhost:5432/cargo_registry ./target/debug/crates-admin enqueue-job check_about_to_expire_token

4. Check the email from the worker's tmp dir

[Turbo87]

🎉