Fix user visible check (#21210)

Fixes #21206

If user and viewer are equal the method should return true.
Also the common organization check was wrong as `count` can never be
less then 0.

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

models/fixtures/user.yml

@@ -345,7 +345,7 @@
   avatar_email: user19@example.com
   num_repos: 2
   is_active: true
-  num_members: 1
+  num_members: 2
   num_teams: 1
 
 -
@@ -572,6 +572,8 @@
   avatar: avatar31
   avatar_email: user31@example.com
   num_repos: 0
+  num_followers: 0
+  num_following: 1
   is_active: true
 
 -
@@ -590,3 +592,23 @@
   avatar_email: user30@example.com
   num_repos: 0
   is_active: true
+
+-
+  id: 33
+  lower_name: user33
+  name: user33
+  login_name: user33
+  full_name: User 33 (Limited Visibility)
+  email: user33@example.com
+  passwd_hash_algo: argon2
+  passwd: a3d5fcd92bae586c2e3dbe72daea7a0d27833a8d0227aa1704f4bbd775c1f3b03535b76dd93b0d4d8d22a519dca47df1547b # password
+  type: 0 # individual
+  salt: ZogKvWdyEx
+  is_admin: false
+  visibility: 1
+  avatar: avatar33
+  avatar_email: user33@example.com
+  num_repos: 0
+  num_followers: 1
+  num_following: 0
+  is_active: true