chore: remove public access modifier in botframework-streaming

[stevengum]

Part 2 of #3518
#minor

Description:
Removed public access modifier from botframework-streaming. botframework-streaming is now eslint compliant.

[coveralls]

Pull Request Test Coverage Report for Build 980184654

• 79 of 79 (100.0%) changed or added relevant lines in 19 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.009%) to 83.747%

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Files with Coverage Reduction	New Missed Lines	%
libraries/botframework-streaming/src/namedPipe/namedPipeServer.ts	1	79.45%
libraries/botframework-streaming/src/webSocket/webSocketTransport.ts	1	84.16%

Totals
Change from base Build 979956236:	-0.009%
Covered Lines:	19516
Relevant Lines:	22077

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💛 - Coveralls

[joshgummersall]

Couple small comments, otherwise LGTM!

[stevengum]

@joshgummersall thanks for the review! This PR is ready, although there are some public surface area changes that I'll mull over later today/tomorrow...

[joshgummersall]

@joshgummersall Joshua Gummersall FTE thanks for the review! This PR is ready, although there are some public surface area changes that I'll mull over later today/tomorrow...

For posterity - we assessed the changes here and determined that they should not cause problems with consumers. We also manually linked this branch against botframework-directlinejs and ran the full build process to ensure compilation did not break.