Tag API calls to /internal/authorized_keys

This allows us to display statistics in Grafana.

CHANGELOG-EE

@@ -9,6 +9,7 @@ v 8.8.0 (unreleased)
   - [Elastic] Add rake task for clearing indexing status
   - Set KRB5 as default clone protocol when Kerberos is enabled and user is logged in (Borja Aparicio)
   - Reduce emails-on-push HTML size by using a simple monospace font
+  - API requests to /internal/authorized_keys are now tagged properly
 
 v 8.7.5
   - No EE-specific changes

lib/api/internal.rb

@@ -58,6 +58,8 @@ module API
       # Get a ssh key using the fingerprint
       #
       get "/authorized_keys" do
+        Gitlab::Metrics.action = 'Grape#/internal/authorized_keys'
+
         fingerprint = params.fetch(:fingerprint) do
           Gitlab::InsecureKeyFingerprint.new(params.fetch(:key)).fingerprint
         end