fix: botbuilder-ai eslint warnings and errors

[joshgummersall]

Title says it all - finally removed warn-only for a package!

[joshgummersall]

I'm happy to be argued with on this, I don't think it provides us a lot of value.

[coveralls]

Pull Request Test Coverage Report for Build 521721127

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 86 unchanged lines in 12 files lost coverage.
• Overall coverage decreased (-0.001%) to 84.744%

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Files with Coverage Reduction	New Missed Lines	%
libraries/botbuilder-ai/src/luisRecognizerOptions.ts	1	81.82%
libraries/botbuilder-ai/src/qnaMakerRecognizer.ts	1	82.5%
libraries/botbuilder-ai/src/qnamaker-utils/generateAnswerUtils.ts	1	89.06%
libraries/botbuilder-ai/src/qnamaker-utils/trainUtils.ts	1	88.89%
libraries/botbuilder-ai/src/luisRecognizerOptionsV2.ts	2	95.65%
libraries/botbuilder-ai/src/qnamaker-utils/activeLearningUtils.ts	3	78.38%
libraries/botbuilder-ai/src/qnamaker-utils/httpRequestUtils.ts	3	81.25%
libraries/botbuilder-ai/src/luisAdaptiveRecognizer.ts	4	83.13%
libraries/botbuilder-ai/src/luisRecognizerOptionsV3.ts	5	91.28%
libraries/botbuilder-ai/src/luisRecognizer.ts	5	93.41%

Totals
Change from base Build 521714205:	-0.001%
Covered Lines:	18185
Relevant Lines:	20484

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💛 - Coveralls

[stevengum]