[UI] Add arrow description in conditional branching on the `Switch` task

Feature description

Consider the following workflow:

id: switch
namespace: dev

inputs:
  - name: language
    type: STRING
    defaults: English

tasks:

  - id: render-language
    type: io.kestra.core.tasks.flows.Switch
    value: "{{ inputs.language }}"
    cases:
      French:
        - id: french
          type: io.kestra.core.tasks.debugs.Return
          format: "The input is {{ inputs.language }}"
      German:
        - id: german
          type: io.kestra.core.tasks.debugs.Return
          format: "The input is {{ inputs.language }}"
    defaults:
      - id: english
        type: io.kestra.core.tasks.debugs.Return
        format: "The input is {{ inputs.language }}"

It would be user-friendly if the cases can be added next to the arrows as follows: