docs(rdb): add encryption activation on existing instances int-add-rdb (#3936)

Author: estellesoulard

managed-databases/postgresql-and-mysql/concepts.mdx

@@ -55,11 +55,17 @@ A [snapshot](/managed-databases/postgresql-and-mysql/how-to/manage-snapshots/) i
 
 ## Encryption at rest
 
+<Message type="important">
+Once activated on a Database Instance, encryption at rest cannot be disabled.
+</Message>
+
 Encryption at rest allows you to permanently encrypt your database data. The data is encrypted at volume level using [LUKS](https://en.wikipedia.org/wiki/Linux_Unified_Key_Setup). At Scaleway `aes-xts-plain64` is used as the default. The management of the encryption key is done by Scaleway.
 
-When you enable encryption at rest, you cannot disable it after database creation. All databases, data (including logs), and snapshots will be encrypted. Logical backup encryption is not currently available.
+All databases, data (including logs), and snapshots will be encrypted. Logical backup encryption is not currently available.
 
-During the beta phase, you can enable encryption on an existing Database Instance by opening a request via a [support ticket](https://console.scaleway.com/support).
+<Message type="note">
+Encryption at rest can be activated after Database Instance creation via the [upgrade endpoint](https://www.scaleway.com/en/developers/api/managed-database-postgre-mysql/#path-database-instances-upgrade-a-database-instance).
+</Message>
 
 Enabling encryption means your database data will be copied into a new, encrypted block volume. This takes approximately 1 hour per 100 GB of storage. When switching volumes, expect a few seconds of downtime towards the end of the copying process.
 

managed-databases/postgresql-and-mysql/how-to/create-a-database.mdx

@@ -38,9 +38,11 @@ Compared to traditional database management, which requires customers to provide
         </Message>
     - Enable [encryption at rest](/managed-databases/postgresql-and-mysql/concepts/#encryption-at-rest) if you want to ensure the permanent encryption of your database data.
         <Message type="important">
-          When you enable encryption at rest, you cannot disable it after database creation. All databases, data (including logs), and snapshots will be encrypted. Logical backup encryption is not currently available.
+          Once activated on a Database Instance, encryption at rest cannot be disabled.
           <br /><br />
-          During the beta phase, you can enable encryption on an existing Database Instance by opening a request via a [support ticket](https://console.scaleway.com/support).
+          All databases, data (including logs), and snapshots will be encrypted. Logical backup encryption is not currently available.
+          <br /><br />
+          Encryption at rest can be activated after Database Instance creation via the [upgrade endpoint](https://www.scaleway.com/en/developers/api/managed-database-postgre-mysql/#path-database-instances-upgrade-a-database-instance).
           <br /><br />
           Enabling encryption means your database data will be copied into a new, encrypted block volume. This takes approximately 1 hour per 100 GB of storage. When switching volumes, expect a few seconds of downtime towards the end of the copying process.
         </Message>