Move pre-CV2 notes to "Legacy Message Component Behavior"

Author: freya022

docs/components/reference.mdx

@@ -66,10 +66,6 @@ All components have the following fields:
 
 The `id` field is optional and is used to identify components in the response from an interaction that aren't interactive components. The `id` must be unique within the message and is generated sequentially if left empty. Generation of `id`s won't use another `id` that exists in the message if you have one defined for another component.
 
-::: info
-Messages preceding components V2 will contain an `id` of `0`, sending `0` is allowed but will be incremented to `1` then follow the numbering rule mentioned above.
-:::
-
 ###### Custom ID
 
 Additionally, interactive components like buttons and selects must have a `custom_id` field. The developer defines this field when sending the component payload, and it is returned in the interaction payload sent when a user interacts with the component. For example, if you set `custom_id: click_me` on a button, you'll receive an interaction containing `custom_id: click_me` when a user clicks that button.
@@ -1176,6 +1172,8 @@ To upload a file with your message, you'll need to send your payload as `multipa
 
 Before the introduction of the `IS_COMPONENTS_V2` flag ([see changelog](/docs/change-log/2025-04-22-components-v2)), message components were sent in conjunction with message content. This means that you could send a message using a subset of the available components without setting the `IS_COMPONENTS_V2` flag, and the components would be included in the message content along with `content` and `embeds`.
 
+Messages preceding components V2 will contain an `id` of `0`, sending back `0` is allowed but will be incremented to 1, then generated sequentially while avoiding duplicates.
+
 Apps using this Legacy Message Component behavior will continue to work as expected, but it is recommended to use the new `IS_COMPONENTS_V2` flag for new apps or features as they offer more options for layout and customization.
 
 :::info