Add last_name to ApiKey users

When we generate a `:common_name` on Users, we check for the presence of
both `first_name` and `last_name`. If either is `nil`, we don't generate
a `common_name`.

ApiKey users only have one name (the name of the ApiKey itself) but we
should set the `last_name` to an empty string. This way, the common name
will still be generated.

Because the `metabase.models.user/insert-new-user!` function requires a
NonBlankString for `first_name` and `last_name` if they're present, I
went back to calling `t2/insert-returning-instances!` directly.

src/metabase/api/api_key.clj

@@ -54,9 +54,13 @@
   (let [unhashed-key (key-with-unique-prefix)
         email        (format "api-key-user-%s@api-key.invalid" (u/slugify name))]
     (t2/with-transaction [_conn]
-      (let [user (user/insert-new-user! {:email      email
-                                         :first_name name
-                                         :type       :api-key})]
+      (let [user (first
+                  (t2/insert-returning-instances! :model/User
+                                                  {:email      email
+                                                   :first_name name
+                                                   :last_name  ""
+                                                   :type       :api-key
+                                                   :password (str (random-uuid))}))]
         (user/set-permissions-groups! user [(perms-group/all-users) group_id])
         (let [api-key (-> (t2/insert-returning-instance! :model/ApiKey
                                                          (-> {:user_id       (u/the-id user)
@@ -93,7 +97,8 @@
           (user/set-permissions-groups! user [(perms-group/all-users) {:id group_id}])))
       (when name
         ;; A bit of a pain to keep these in sync, but oh well.
-        (t2/update! :model/User (:user_id api-key-before) {:first_name name})
+        (t2/update! :model/User (:user_id api-key-before) {:first_name name
+                                                           :last_name ""})
         (t2/update! :model/ApiKey id (with-updated-by {:name name}))))
     (let [updated-api-key (-> (t2/select-one :model/ApiKey :id id)
                               (t2/hydrate :group :updated_by))]

src/metabase/models/user.clj

@@ -336,7 +336,7 @@
    [:email      ms/Email]
    [:first_name [:maybe ms/NonBlankString]]])
 
-(mu/defn insert-new-user!
+(mu/defn ^:private insert-new-user!
   "Creates a new user, defaulting the password when not provided"
   [new-user :- NewUser]
   (first (t2/insert-returning-instances! User (update new-user :password #(or % (str (random-uuid)))))))