chore(iso): drop unreachable else branches in build helpers

nomarchy-build-iso and nomarchy-build-live-iso both ran under set -e
but then wrapped nix build in an if [ \$? -eq 0 ] block with an else
that printed "Error: ISO build failed." and exit 1. set -e aborts the
script the instant nix build returns non-zero, so the else branch was
never reached — the user saw nix build's own error output and the
script exited.

Removed the dead conditional. Behaviour is identical.

features/scripts/utils/nomarchy-build-iso

@@ -4,15 +4,8 @@ set -e
 # Build the Nomarchy Installer ISO declaratively using the flake.
 
 echo "Building Nomarchy Installer ISO..."
-
-# The output will be a symlink named 'result' in the current directory
 nix build .#nixosConfigurations.nomarchy-installer.config.system.build.isoImage
 
-if [ $? -eq 0 ]; then
-    ISO_PATH=$(readlink -f result/iso/*.iso)
-    echo "Success! ISO built at: $ISO_PATH"
-    echo "You can now burn this to a USB drive using 'dd' or 'etcher'."
-else
-    echo "Error: ISO build failed."
-    exit 1
-fi
+ISO_PATH=$(readlink -f result/iso/*.iso)
+echo "Success! ISO built at: $ISO_PATH"
+echo "You can now burn this to a USB drive using 'dd' or 'etcher'."