[FIX] package: add rolldown binaries to optional dependencies

NPM has an issue that affected the package-lock.json by pruning OS
optional dependencies (See npm/cli#7961). The issue has been fixed (npm/cli#8184)
in NPM v11.3 but not backported.

During commit ff7f083, we ran npm install, and so the package-lock.json
was updated to remove the optional dependencies for rolldown binaries.
Which caused issues for users each time they run npm install as they
were not present anymore in the package-lock.json.

This commit adds the rolldown binaries to the optional dependencies of
this project to avoid them being pruned again in the future.

See #7157

closes #8385

Task: 0
Part-of: #8445
Signed-off-by: Lucas Lefèvre (lul) <lul@odoo.com>
Signed-off-by: Pierre Rousseau (pro) <pro@odoo.com>

Author: pro-odoo