Fixed compatibility between compute groups in MetricCollection and prefix/postfix arg

[SkafteNicki]

What does this PR do?

Fixes #1006

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[codecov]

Codecov Report

Merging #1008 (00f381c) into master (d0e14fe) will increase coverage by 1%.
The diff coverage is n/a.

❗ Current head 00f381c differs from pull request most recent head 34b6d03. Consider uploading reports for the commit 34b6d03 to get more accurate results

@@          Coverage Diff           @@
##           master   #1008   +/-   ##
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+ Coverage      94%     95%   +1%     
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  Files         180     180           
  Lines        7666    7668    +2     
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+ Hits         7231    7274   +43     
+ Misses        435     394   -41