Add docs for transient-users how to prevent profile-review (#28889)

Signed-off-by: Captain-P-Goldfish <captain.p.goldfish@gmx.de>

#relatesTo #26637

docs/transient-users.md

@@ -60,4 +60,11 @@ When using transient users, you should be aware of the following:
 - Technically, transient user data is stored as part
   of the user session. It thus increases the session size.
 
+- The transient user login uses the `first broker login` authentication-flow for each authentication causing
+  a profile review for each authenticated user each time a user authenticates. To prevent this behaviour
+  copy the `first broker login` authentication-flow, disable the `Review Profile` step and assign the new
+  authentication-flow to the `Identity Provider` configuration by selecting it in the `First login flow`
+  selection-box of the `Identity Provider` configuration.
+
+
 </@tmpl.guide>