Fix ./setup install comand (backport #10417)

[mergify]

Running ./setup install will give you an error:

fromFlag NoFlag. Use fromFlagOrDefault
CallStack (from HasCallStack):
  error, called at src/Distribution/Simple/Flag.hs:110:19 in Cabal-3.15.0.0-inplace:Distribution.Simple.Flag
  fromFlag, called at src/Distribution/Simple/Register.hs:161:16 in Cabal-3.15.0.0-inplace:Distribution.Simple.Register

This seems to not be tested anywhere and most people will use ./setup register in any case, but we should fix this for the next point release in 3.14 series. # Please enter the commit message for your changes. Lines starting

Fixes #10416

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This is an automatic backport of pull request #10417 done by [Mergify](https://mergify.com).