Fix for issue product-is/21659

[kumardeepak5]

Purpose

This PR may resolve wso2/product-is#21659

Goals

This PR ensures that a 400 status code is returned instead of a 500 when the API endpoint /recovery/password/recover encounters an invalid channel ID in the request body during account recovery v2.

Behavior After Fix:

Below is the Sample Request & response.
Request [Recover Password with invalid channel Id]

curl --location 'https://localhost:9443/api/users/v2/recovery/password/recover' \
--header 'Content-Type: application/json' \
--header 'Authorization: Basic <base64 username:password>' \
--data '{
  "recoveryCode": "<recovery-code>",
  "channelId": "<invalid-channel-id>"
}'

Response [Recover Password with invalid channel Id]
Response Code - 400

{
    "code": "UAR-10004",
    "message": "Bad Request",
    "description": "Channel ID does not exist",
    "traceId": "<trace-id>"
}

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