Move block-action.ts to @slack/types

Description

The types in block-action.ts are super useful for just interacting with the Slack API in other packages, like @slack/web-api. We pull in @slack/bolt just to use these types. It would be great if these types could be moved to @slack/types to avoid having to pull in all of @slack/bolt just to use them.

What type of issue is this? (place an x in one of the [ ])

• bug
• enhancement (feature request)
• question
• documentation related
• example code related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

Bug Report

Filling out the following details about bugs will help us solve your issue sooner.

Reproducible in:

package version: 3.11.0

node version: 16.x

OS version(s): Ubuntu 20.04

Steps to reproduce:

1. npm i @slack/types
2. import various button action types :)

Expected result:

Leverage the awesome button action types

Actual result:

Have to get them from @slack/bolt instead

Attachments:

I picked the funny image option:

Locate block-action.ts and inspect how its types are exported from @slack/bolt and how @slack/types exposes its public types. Trace the relevant imports and package tests or build checks, then verify that consumers can import these button action types from @slack/types without depending on @slack/bolt.