[Feature Request] Adding responses to commands in the text subchannel of a voice channel

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### Is your feature request related to a problem? Please describe.

Since discord provides text subchannels for each voice channel, not using separate on-demand channels is necessary for larger discord servers with many voice channels. Unfortunately, Jmusic does not support responding to commands in text subchannels. (Perhaps this is because slash commands are not supported at the moment?)

### What is your ideal solution to the problem?

Adds a response to a command in the text subchannel of a voice channel. In theory, discord already provides a response API that can respond to any text channel content without discrimination.

### How would this feature be used?

Enter a voice channel, then use commands in the text subchannel of the voice channel, and the bot's response is output in this text subchannel.

### Additional Info

_No response_

### Checklist

- [X] I have checked [the documentation](https://jmusicbot.com/) to make sure this feature doesn't already exist
- [X] I have searched for [similar feature requests](https://github.com/jagrosh/MusicBot/labels/enhancement)
- [X] I have confirmed that my requests is **not** on the [list of things that will not be added](https://jmusicbot.com/things-that-wont-be-added)
- [ ] I am running the latest version of the bot: 

No files or tests are named. Start by tracing how commands receive and send responses for Discord channels, then check how voice-channel text subchannels are represented and handled. Done means commands entered in a voice channel's text subchannel receive the bot's response there.

Written by the indexing model from the issue text.