Dashboard: fix nodes calculation

[coveralls]

Pull Request Test Coverage Report for Build 3688

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 92.221%

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Files with Coverage Reduction	New Missed Lines	%
src/dashboard/server/api/v2/controllers/cluster/team/index.js	1	98.25%
<!--	Total:	1		-->

Totals
Change from base Build 3685:	-0.2%
Covered Lines:	968
Relevant Lines:	1038

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💛 - Coveralls