Prevent Cortana from trying to use suggested actions in prompts

[v-kydela]

Fixes microsoft/botbuilder-dotnet#1173

Description

I have modified choiceFactory.ts by removing hasMessageFeed and supportsCardActions from the if condition so that now a channel must support suggested actions in order for the SDK to automatically select them as the list style. I have also deleted those local variables for cleanliness since they aren't being used anywhere else.

[coveralls]

Pull Request Test Coverage Report for Build 2638

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 82.418%

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Files with Coverage Reduction	New Missed Lines	%
libraries/botbuilder-dialogs/src/choices/channel.ts	2	68.18%

Totals
Change from base Build #1864:	-0.1%
Covered Lines:	2738
Relevant Lines:	3194

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💛 - Coveralls

[stevengum]

Please add a test to cover the scenario mentioned in microsoft/botbuilder-dotnet#1173

[v-kydela]

@stevengum - I just pushed another commit

[Stevenic]