If both webhook URL and bot token are specified, action will run twice

[filmaj]

Description

I think this mostly just affects running the tests in this repo. Currently, each individual test in this repo's GH Action CI workflow file executes possibly multiple times because of this bug.

If a bot token is specified via an environment variable, then this conditional block will execute, which might result in posting or updating a message.

If a webhook URL is specified via an environment varaible, then this conditional block will execute, possibly POSTing to the webhook URL.

If you consume this action and use it using a bot token, but also specify the webhook URL environment variable, the action will POST to the webhook URL.

I think the solution is to do either-or: either use the bot token, or use the webhook URL. A fix for this issue should also clean up the usage of the webResponse variable in the code, as this is only set and used in the bot-token scenario.