[#6624] port: [#4452][#4456][#4460][botframework-streaming] Should reject pending requests on disconnection

[ceciliaavila]

Fixes #6624

Description

This PR ports the changes from PR#4461 to reject all pending requests when the websocket is disconnected.

Specific Changes

• Added new RejectAllResponses method in RequestManager class.
• Added call to RejectAllResponses in OnConnectionDisconnected of WebSocketClient.
• Added a unit test to cover the new method in RequestManagerTests.
• Refactored WebSocketTransportTests to follow the implementation in JS:
  • Move WebSocketClient and WebSocketServer tests to the new class WebSocketClientServerTests.
  • Move the FauxSock class to the Utilities folder for reuse by the test classes.

Testing

These images show the pending requests being rejected after the fix and the new unit tests passing.

[coveralls]

Pull Request Test Coverage Report for Build 349985

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.003%) to 79.09%

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Files with Coverage Reduction	New Missed Lines	%
/libraries/AdaptiveExpressions/BuiltinFunctions/GetNextViableTime.cs	1	90.91%
/libraries/AdaptiveExpressions/BuiltinFunctions/GetPreviousViableTime.cs	1	90.91%
/libraries/Microsoft.Bot.Streaming/Transport/WebSocket/WebSocketClient.cs	2	78.87%

Totals
Change from base Build 349053:	-0.003%
Covered Lines:	25830
Relevant Lines:	32659

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💛 - Coveralls

[BruceHaley]

✔️ No Binary Compatibility issues for Microsoft.Bot.Streaming.dll