Trailing new lines in presets are different between AI model webchat providers

[littleboot]

Presets trailing new lines in prompt prefix are incorrect and depending on the AI provider (same behavior in firefox and chrome)

For example my gemini prefix has a single trailing newline char \n but two are inserted after the system prompt,

<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>

 first line

NOTE there also is an additional space before the chat content first line

Example gpt chat window:

<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>
 first line

mostly correct, but an additonal space before the chat content (probably intentional)

Example qwen response (identical to gpt)

Example Claude:

<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system> first line

ignores the new line all together.

Why I want this fixe.

I want to be able to read back my chats in the webchat UI, for this I want to have a newline between the prompt and the chat context.
Maybe replace the default space that is used to separate the prompt prefix from the chat content with a newline char \n still a single character and makes reading back the chat easier.

Settings.json:

    "codeWebChat.chatPresetsForNoContext": [
        {
            "name": "Gemini pro",
            "chatbot": "Gemini",
            "promptPrefix": "<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>\n",
            "model": "pro"
        },
        {
            "name": "ChatGPT thinking",
            "chatbot": "ChatGPT",
            "promptPrefix": "<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>\n",
            "options": [
                "thinking"
            ]
        },
        {
            "name": "Qwen",
            "chatbot": "Qwen",
            "promptPrefix": "<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>\n",
            "options": [
                "thinking"
            ]
        },
        {
            "name": "Claude",
            "chatbot": "Claude",
            "promptPrefix": "<system>You're a helpful coding assistant, follow these rules when answering:`talk like a pirate`</system>\n",
            "model": "sonnet-4-5"
        }
    ],

I'm using a windows 11 PC with vscodium

[robertpiosik]

Prompt prefix and suffix will be removed from webchat providers.

The expected workflow will be with prompt templates:

I hope to ship these changes this week.