chore: Update create-vsix to support multi-vsix and shared bot logic

[TwitchBronBron]

Summary

• Adds a workflow_dispatch trigger (with a pr input accepting a PR number or full URL) so this can be tested without needing a labeled PR
• Forwards branch, pr, and repo to vscode-brightscript-language's create-vsix workflow, which now interprets these inputs itself and posts the download-links comment directly on the originating PR
• Drops the local "Add comment to PR" step since it's now redundant — the comment is posted by vscode-brightscript-language's workflow instead
• Keeps wait-for-completion: true so this job's pass/fail status still reflects whether the actual vsix build succeeded

[rokucommunity-bot]

Hey there! I just built a new version of the vscode extension based on 699e7f1.

Download:

• brightscript (replaces store version)
• brightscript-temp (side-by-side install)

Install instructions.