[stable8] fix(NcActions): improve performance by only computing popover maxHeight on demand

[backportbot]

Backport of #7808

Warning, This backport's changes differ from the original and might be incomplete ⚠️

Todo

• Review and resolve any conflicts
• Amend HEAD commit to remove the line stating to skip CI

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[Antreesy]

I kept triggerRandomId as it's used differently from Vue 3 branch

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.62%. Comparing base (47e8775) to head (5e06367).
⚠️ Report is 6 commits behind head on stable8.

Additional details and impacted files

@@           Coverage Diff            @@
##           stable8    #7815   +/-   ##
========================================
  Coverage    44.62%   44.62%           
========================================
  Files          188      188           
  Lines         4710     4710           
  Branches      1226     1226           
========================================
  Hits          2102     2102           
  Misses        2513     2513           
  Partials        95       95           

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