fix: dashboard panel scale affecting position

[ianshade]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  Bug fix (UI)

• What is the current behavior? (You can also link to an open issue here)
  Setting a Scale other than 1 on some dashboard panels (NextInfoPanel and PieceCountdownPanel) affects their position change. Cause: changing fontSize on an element positioned using em.

• What is the new behavior (if this is a feature change)?
  Positioning on these panels is fixed to work exactly as other panels.

• Other information:
  The additional variable (--dashboard-panel-scale) is not used by these panels, but used by TV 2's keyboard map. Can it stay there?

Status

• Code documentation for the relevant parts in the code have been added/updated by the PR author
• The functionality has been tested by the PR author
• The functionality has been tested by NRK

[codecov-commenter]

Codecov Report

Merging #655 (aa2b73d) into release39 (5738a17) will not change coverage.
The diff coverage is n/a.

❗ Current head aa2b73d differs from pull request most recent head ae09803. Consider uploading reports for the commit ae09803 to get more accurate results

@@            Coverage Diff             @@
##           release39     #655   +/-   ##
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  Coverage      67.87%   67.87%           
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  Files            275      275           
  Lines          19160    19160           
  Branches        4316     4316           
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  Hits           13005    13005           
  Misses          6078     6078           
  Partials          77       77           

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