chatbot: support for `UserRoleRequired` at the `SlackChannelConfiguration` class

[badmintoncryer]

Describe the feature

Enable to specify userRoleRequired property at the SlackChannelConfiguration class.

Use Case

SlackChannelConfiguration class does not support for specifying userRoleRequired property.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.141.0

Environment details (OS name and version, etc.)

irrelevant

[ashishdhingra]

UserRoleRequired is a supported property per AWS::Chatbot::SlackChannelConfiguration and should be supported in SlackChannelConfiguration class.