Files Service Fix

[jonwinton]

Use includes rather than indexOf

[coveralls]

Pull Request Test Coverage Report for Build 1940

• 13 of 13 (100.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 1937:	0.0%
Covered Lines:	4189
Relevant Lines:	4189

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💛 - Coveralls