fix: clarify plain text password import (#2081)

* fix: clarify plain text password import

* fix: clarify plain text password import

* fix: clarify plain text password import

* chore: text bug

Author: vinckr

docs/kratos/manage-identities/25_import-user-accounts-identities.mdx

@@ -158,6 +158,10 @@ self-service flows.
 The password `the-password` will then be hashed according to the configured password hashing algorithm and stored in the database.
 The identity will be able to sign in using `[email protected]` and `the-password` as credentials.
 
+When importing clear text passwords, the process may be slower than expected because each password must be hashed during the
+import process. If you are batch importing more than 20 clear text passwords, please hash the passwords before importing them to
+avoid timeouts.
+
 ### Hashed passwords
 
 To import a hashed password, provide the hashed password in the JSON payload.