Add oauth_settings.state_validation_enabled to customize the OAuth flow

[seratch]

Having a state parameter in OAuth flow is a highly recommended practice for security in general. However, when Slack org/workspace admins install an app from their app management page, there is no way to customize the authorize url.

Thus, to support the admins' use case, we can introduce a new option to disable state parameter validation in the OAuth flow. We are going to add flag options to App and AsyncApp plus modify the internal logic.

• oauth_settings.state_validation_enabled: bool flag (default: True)
• async_oauth_settings.state_validation_enabled: bool flag (default: True)

https://github.com/slackapi/bolt-python/tree/v1.8.1/slack_bolt/oauth

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

• slack_bolt.App and/or its core components
• slack_bolt.async_app.AsyncApp and/or its core components
• Adapters in slack_bolt.adapter
• Others

Requirements

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