chore: Rebrand all Node samples to use App instead of Bot

[vinay-google]

No description provided.

[snippet-bot]

Here is the summary of possible violations 😱

There is a possible violation for not having product prefix.

• node/avatar-app/index.js:17, tag hangouts_chat_avatar_bot

The end of the violation section. All the stuff below is FYI purposes only.

---

Here is the summary of changes.

You are about to add 1 region tag.

• node/avatar-app/index.js:17, tag hangouts_chat_avatar_bot

You are about to delete 1 region tag.

• node/avatar-bot/index.js:17, tag hangouts_chat_avatar_bot

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment