[Fleet] fleet misrenders yaml string literal

[efd6]

Fleet appears to render invalid yaml in some cases. Finer details in internal backlink that will appear below, but the summary is that the user is using the CEL input and has a program that looks like this:

bytes(get(state.url).Body).as(body, {
  "events": body.decode_json().field
})

but is rendered as this in the pre-config:

          program: |4-
               bytes(get(state.url).Body).as(body, {
            "events": body.decode_json().field
            })

This is broken because correct parsers expect the indentation to be 4, but all lines after the first are indented at 2. This breaks tools that need to be able to consume diagnostic bundles.

The stack version being used here is v8.15.2.

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)