fix(allByLabelText): forEach on NodeList is not supported in edge

[eps1lon]

What:

fixes crash in Edge when using getAllByLabelText

Why:

forEach is not implemented in NodeList in edge 15

How:

Convert NodeList to array before using forEach

Checklist:

• [ ] Documentation added to the
  docs site
• [ ] I've prepared a PR for types targeting
  DefinitelyTyped
• Tests (will run codesandbox canary on Material-UI
• Ready to be merged
  

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[codecov]

Codecov Report

Merging #463 into beta will not change coverage by %.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              beta      #463   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           22        22           
  Lines          419       419           
  Branches       100       100           
=========================================
  Hits           419       419           

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