health: Set default port based on existing constant
health: Set default port based on existing constant

Default port constant already exists, but a literal
integrer was used in the flag definition logic here.

Signed-off-by: Ilya Dmitrichenko <59b6733e47280dc0842a1e64fb2a9c742d686e46@gmail.com>

michi-covalent/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium