fix: don't ignore allow_multiselect when serializing

[AstreaTSS]

Pull Request Type

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

Description

Quick bugfix to make sure allow_multiselect is exported when serializing. Can't test right now, but the change is simple.

Changes

• Remove no_export_meta from metadata of allow_multiselect.

Related Issues

Test Scenarios

import interactions as ipy

@ipy.slash_command()
async def test(ctx: ipy.SlashContext):
    poll = Poll.create("Test?", duration=1, answers=["1!", "2."], allow_multiselect=True)
    await ctx.send(poll=poll)

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