Make API::Helpers find a project with only one query

Signed-off-by: Rémy Coutable <remy@rymai.me>

changelogs/unreleased/22373-reduce-queries-in-api-helpers-find_project.yml

+---
+title: 'Make API::Helpers find a project with only one query'
+merge_request: 7714
+author:

lib/api/helpers.rb

@@ -76,7 +76,12 @@ module API
     end
 
     def find_project(id)
-      project = Project.find_with_namespace(id) || Project.find_by(id: id)
+      project =
+        if id =~ /^\d+$/
+          Project.find_by(id: id)
+        else
+          Project.find_with_namespace(id)
+        end
 
       if can?(current_user, :read_project, project)
         project