packaging/dependencies: Use boost without enableIcu

This reduces the closure size on master by 40MiB.

```
$ nix build github:nixos/nix/1e822bd4149a8bce1da81ee2ad9404986b07914c#nix-store --out-link closure-on-master
$ nix build .#nix-store -L --out-link closure-without-icu
$ nix path-info --closure-size -h ./closure-on-master
/nix/store/8gwr38m5h6p7245ji9jv28a2a11w1isx-nix-store-2.29.0pre  124.4 MiB
$ nix path-info --closure-size -h ./closure-without-icu
/nix/store/k0gwfykjqpnmaqbwh23nk55lhanc9g24-nix-store-2.29.0pre   86.6 MiB
```

(cherry picked from commit f3090ef)

Author: xokdvium

packaging/dependencies.nix

@@ -63,6 +63,7 @@ scope: {
         "--with-coroutine"
         "--with-iostreams"
       ];
+      enableIcu = false;
     }).overrideAttrs
       (old: {
         # Need to remove `--with-*` to use `--with-libraries=...`