port: Support timestamp without timezone postfix in getTimeOfDay

[Danieladu]

Fixes #3638

Cause of the issue

• The input of datetime functions (like getTimeOfDay), only accepts the original datetime format("yyyy-MM-ddTHH:mm:ss.fffZ")
• The output format of convertFromUTC was changed from "yyyy-MM-ddTHH:mm:ss.fffZ" to "yyyy-MM-ddTHH:mm:ss.fffffffK" in R12, which is correct because a time converted from UTC should no longer have the "Z" postfix. This is also aligned with WDL's convention.
• Then the result of convertFromUTC doesn't fit in the input of getTimeOfDay, error occurs.

In a summary, the current datetime functions input format is too strict.

Changes

Expand the input of date time functions to cover the case of timestamp without timezone postfix.

[coveralls]

Pull Request Test Coverage Report for Build 815502809

• 24 of 25 (96.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 85.434%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
libraries/adaptive-expressions/src/builtinFunctions/getTimeOfDay.ts	23	24	95.83%

Files with Coverage Reduction	New Missed Lines	%
libraries/botbuilder-lg/src/templateExtensions.ts	1	84.48%

Totals
Change from base Build 815502491:	-0.003%
Covered Lines:	19225
Relevant Lines:	21402

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💛 - Coveralls

[joshgummersall]

@Danieladu what's the status of this?

[Danieladu]

I have marked it as "Ready for review"