fix: Teams Meeting Notification interface structure changes

[singhk97]

Fixes #4415

Description

• Refactored types and interfaces associated with sendMeetingNotification api call, so that it can be extended without any breaking changes. And by 'extend`, I mean adding new types, making-optional existing properties and adding properties to existing interfaces.

Specific Changes

• Made channelData an optional property
• Updated the type of onBehalfOf property to be a list of MeetingOnBehalfOf objects.
• Notification payload type expected the notification parameter in sendMeetingNotification API function is MeetingNotification. Currently it is equal to TargetedMeetingNotification. However it can made be a union of any arbitrary type. This makes the payload type extensible without any breaking changes.
• The request body mappers were simplified so that any value passed to the value property would be serialized without any hard coded constraints.
• surfaces now is a list of MeetingSurface type. Just like MeetingNotification it can be a union of any arbitrary type. Making it possible to have more than one type of surface object in the list of surfaces.
• Name change: All the TeamsMeeting prefixed type names are not just Meeting. This conforms to the standards of meetings-related type within the SDK.

Testing

• Performed end-to-end test
• Unit tests remain the same

[coveralls]

Pull Request Test Coverage Report for Build 4108444092

• 10 of 10 (100.0%) changed or added relevant lines in 2 files are covered.
• 5 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.001%) to 84.652%

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Files with Coverage Reduction	New Missed Lines	%
libraries/botframework-streaming/src/webSocket/nodeWebSocket.ts	5	86.27%

Totals
Change from base Build 3841042555:	0.001%
Covered Lines:	19998
Relevant Lines:	22387

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💛 - Coveralls

[YunnyChung]

First PR review: leaving a few comments :)

[YunnyChung]

Follow-up

[YunnyChung]

A follow up comment :)

[YunnyChung]

Looks good to me! Thank you :)