Command line flags should override freeze file flags.

[bgohla]

Describe the feature request
A simple description of what you would like to be added to Cabal.

Given a project as follows:

$ cat cabal-freeze-bug.cabal
cabal-version:      3.0
name:               cabal-freeze-bug
version:            0.1.0.0
synopsis:           n
-- description:
license:            BSD-2-Clause
license-file:       LICENSE
author:             Björn Gohla
maintainer:         bjorn.gohla@scrive.com
-- copyright:
category:           Testing
build-type:         Simple
extra-doc-files:    CHANGELOG.md
-- extra-source-files:

flag some-flag
     description: a flag that does nothing
     default: True
   
common warnings
    ghc-options: -Wall

executable cabal-freeze-bug
    import:           warnings
    main-is:          Main.hs
    -- other-modules:
    -- other-extensions:
    build-depends:    base ^>=4.18.2.1
    hs-source-dirs:   app
    default-language: Haskell2010
$ cat cabal.project.freeze 
active-repositories: hackage.haskell.org:merge
constraints: any.base ==4.18.2.1,
             cabal-freeze-bug +some-flag,
             any.ghc-bignum ==1.3,
             any.ghc-prim ==0.10.0,
             any.rts ==1.0.2
index-state: hackage.haskell.org 2024-06-14T08:17:16Z

running

cabal build -f-some-flag

should build the cabal-freeze-bug package with the flag turned off, instead of failing with a resolution conflict.

(Likewise for cabal build -c"cabal-freeze-bug -some-flag")

Additional context
Related to #10439