fix: define nextest dev profile

[bradleystachurski]

We recently introduced exporting CARGO_PROFILE="dev" when sourcing scripts/_common.sh (see: https://github.com/fedimint/fedimint/blob/f001570/scripts/_common.sh#L14). We need to define a dev profile for nextest or just test-ci-all fails locally with

nix@lenovo-m75q-ubuntu:~/fedimint$ just test-ci-all
./scripts/tests/test-ci-all.sh
Pre-building workspace...
    Finished dev [unoptimized + debuginfo] target(s) in 0.26s
Pre-building tests...
error: profile `dev not found (known profiles: ci, default, default-miri)`
error: Recipe `test-ci-all` failed on line 19 with exit code 96