fix(report): building the wrong derivation for home-manager

Small typo that was breaking this script T-T:

```bash
# Wrong:
nix build --print-out-paths ".#homeConfigurations.$config.activationPackages"

# Correct:
nix build --print-out-paths ".#homeConfigurations.$config.config.home.activationPackage"
```

scripts/create-report.sh

@@ -51,7 +51,7 @@ pkgs_json() {
 hm_configs_json() {
   for config in $hmConfigs; do
     log "Building $config"
-    path=$(nix build --print-out-paths ".#homeConfigurations.$config.activationPackages")
+    path=$(nix build --print-out-paths ".#homeConfigurations.$config.config.home.activationPackage")
     closure_size "$config" "$path"
   done
 }