Having the ability to add arbitrary chat message of arbitrary role

[anthonyAttentive]

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Bug

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I added the following prompt template (1 system node and 2 user nodes) and the UI does not show the second user node.
It will also be good to be able to add whatever role I want instead of being forced to add the pair "assistant + user" pair always

name: Text Summarizer
description: Summarizes input text concisely
model: openai/gpt-4o-mini
modelParameters:
  temperature: 0.5
messages:
  - role: system
    content: You are a text summarizer. Your only job is to summarize text given to you.
  - role: user
    content: |
      Summarize the given text, beginning with "Summary -":
      <text>
      {{input}}
      </text>
  - role: user
    content: Use a {{tone}} tone.

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