docs: Fix typo in FQDN metric name
docs: Fix typo in FQDN metric name

Signed-off-by: Chris Tarazi <711c73f64afdce07b7e38039a96d2224209e9a6c@isovalent.com>

cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium