feat: add custom data and configs to be used in custom widgets.

[Saifallak]

Description

before v2.x release i need this simple edit, as it's a breaking change.
More work towards the custom data widgets.
because i'm creating my custom widgets.
so I need the message config be passed too.

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• have followed the Contributor Guide when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

Migration instructions

Add MessageConfiguration to customMessageBuilder wherever you use it.

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

[vatsaltanna-simformsolutions]

I believe this requirement can be handled at the app level.

[Saifallak]

I believe this requirement can be handled at the app level.

How?, any examples?
Because according to package implementation its noy possible

[aditya-css]

Hey @Saifallak,
Thank you for contributing. Adding a customData can be beneficial for any custom metadata as mentioned in the issue #354. The other things added in custom message builder can be avoided. Can you please let me know to if you can update accordingly?