Ensure we use the link returned from ServiceControl to retrieve the message body

[johnsimons]

Describe the suggested improvement

In

ServicePulse/src/Frontend/src/components/failedmessages/MessageView.vue

Line 147 in 34addf2

const response = await useFetchFromServiceControl(`messages/${message.message_id}/body`);

we are constructing a url to retrieve the message body.
We should instead retrieve the body_url from the payload that comes from the REST API.

Additional Context

No response