ext.tasks - change_interval throws an error if used before the task has run

[polidano10]

Summary

You cannot change the interval of a task if it has not executed at least once.

Reproduction Steps

Create a loop, start it, and change its interval before it has time to execute even once.

Minimal Reproducible Code

import os

import disnake
from disnake.ext import tasks, commands
import dotenv

dotenv.load_dotenv()
TOKEN = os.getenv('BOT_TOKEN')
bot_intent = disnake.Intents.none()
bot = commands.InteractionBot(intents=bot_intent)


@bot.event
async def on_ready():
    test_loop.start()
    test_loop.change_interval(minutes=1)

@tasks.loop(minutes=5)
async def test_loop():
    return


def main():
    bot.run(TOKEN)

if __name__ == '__main__':
    main()

Expected Results

The interval should be changed without error.

Actual Results

Ignoring exception in on_ready
Traceback (most recent call last):
  File "venv\Lib\site-packages\disnake\client.py", line 738, in _run_event
    await coro(*args, **kwargs)
  File "main.py", line 18, in on_ready
    test_loop.change_interval(minutes=1)
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "venv\Lib\site-packages\disnake\ext\tasks\__init__.py", line 697, in change_interval
    self._next_iteration = self._get_next_sleep_time()
                           ~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "venv\Lib\site-packages\disnake\ext\tasks\__init__.py", line 563, in _get_next_sleep_time
    return self._last_iteration + datetime.timedelta(seconds=self._sleep)
           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TypeError: unsupported operand type(s) for +: '_MissingSentinel' and 'datetime.timedelta'

Intents

None

System Information

- Python v3.13.0-final
- disnake v2.10.1-final
    - disnake importlib.metadata: v2.10.1
- aiohttp v3.11.16
- system info: Windows 10 10.0.19045 AMD64

Checklist

• I have searched the open issues for duplicates.
• I have shown the entire traceback, if possible.
• I have removed my token from display, if visible.

Additional Context

No response