Make it easy to prompt user for input in ChatFeed

[ahuang11]

Closes #7138

Inspired by https://discourse.holoviz.org/t/panel-chat-interface/7505?u=ahuang11

Wondering if the method should be renamed to simply prompt or prompt_user or require_input

Screen.Recording.2024-08-14.at.5.11.51.PM.mov

import panel as pn

pn.extension()


def prompt_callback(form, instance):
    instance.stream(f"I like {form.value} too!", user="Assistant")


async def callback(message, user, instance):
    if "ice cream" in message.lower():
        form = pn.widgets.TextInput(
            name="Favorite Ice Cream", placeholder="Enter your favorite ice cream"
        )
        instance.prompt_input(
            form, prompt_callback, predicate=lambda form: form.value
        )
        return
    return f"I don't care about {message}"


chat = pn.chat.ChatInterface(callback=callback)

chat.show()

I think this can also be generalized to allow editing existing ChatMessages.

Would like your feedback on this @MarcSkovMadsen and @philippjfr

[codecov]

Codecov Report

Attention: Patch coverage is 97.72727% with 3 lines in your changes missing coverage. Please review.

Project coverage is 82.19%. Comparing base (45809a8) to head (69ca93c).
Report is 2 commits behind head on main.

Files	Patch %	Lines
panel/tests/chat/test_feed.py	96.55%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7148      +/-   ##
==========================================
+ Coverage   82.16%   82.19%   +0.03%     
==========================================
  Files         328      328              
  Lines       49075    49206     +131     
==========================================
+ Hits        40321    40446     +125     
- Misses       8754     8760       +6     

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[ahuang11]

Screen.Recording.2024-08-16.at.10.02.16.PM.mov