io.home-assistant: convert sensor values to the thingtalk units

[coveralls]

Pull Request Test Coverage Report for Build 1728

• 6 of 35 (17.14%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.7%) to 39.839%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
main/com.spotify/src/api/search_query.ts	0	1	0.0%
main/io.home-assistant/sensor.js	6	34	17.65%
<!--	Total:	6	35	17.14%	-->

Files with Coverage Reduction	New Missed Lines	%
main/com.bing/index.js	1	57.93%
<!--	Total:	1		-->

Totals
Change from base Build 1717:	-0.7%
Covered Lines:	1381
Relevant Lines:	3171

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💛 - Coveralls