fix: correct expire property for interaction ctx

[AstreaTSS]

Pull Request Type

• Feature addition
• Bugfix
• Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

Turns out BaseInteractionContext does not handle either expires_at or expired correctly. This PR fixes that.

Changes

• Correct typehint of expires_at.
• Make expires_at consider deferrals.
• Make expired use Timestamp instead of naive datetime.

Related Issues

Fixes #1623.

Test Scenarios

import asyncio

@interactions.slash_command()
async def test(ctx: interactions.SlashContext):
    await ctx.defer()
    await asyncio.sleep(10)
    print(ctx.expired)  # should return false, but just errors out
    await ctx.send("Hello!")

Python Compatibility

• I've ensured my code works on Python 3.10.x
• I've ensured my code works on Python 3.11.x

Checklist

• I've run the pre-commit code linter over all edited files
• I've tested my changes on supported Python versions
• I've added tests for my code, if applicable
• I've updated / added documentation, where applicable