Using an empty prefix (or /) in an http.listeners in the configuration crashes on startup

[sandhose]

Since 0.14.0, the following configuration crashes the server on startup:

http:
  listeners:
    - name: "web"
      prefix: "/"
      resources:
        - name: discovery
        - name: human
        - name: oauth
        - name: assets
        - name: compat
        - name: graphql
        - name: adminapi
      binds:
        - address: "[::]:1234"
    - name: "internal"
      resources:
        - name: health
        - name: prometheus
      binds:
        - host: localhost
          port: 2345

with the following message:

thread 'main' panicked at crates/cli/src/server.rs:243:32:
Nesting at the root is no longer supported. Use merge instead.

The workaround is to remove the prefix property, or set it to null/~

http:
  listeners:
    - name: "web"

      # Comment it out
      #prefix: "/"

      # Set it to ~
      prefix: ~

      # Set it to null
      prefix: null