livestream chat: use commentron, respect default channel

[ktprograms]

PR Checklist

Please check all that apply to this PR using "x":

• [x] I have checked that this PR is not a duplicate of an existing PR (open, closed or merged)
• [x] I have checked that this PR does not introduce a breaking change

PR Type

What kind of change does this PR introduce?

• [x] Bugfix
• [x] Feature

Fixes

Issue Number: N/A

What is the current behavior?

Unable to send chat messages on livestreams.

What is the new behavior?

Fixed sending chat messages on livestreams by using commentron create. Also respect default channel when commenting.

[akinwale]

@ktprograms Let me know when this is ready to merge.