configure GHC: reduce verbosity of newer version warn to info

[juhp]

"Warning: Unknown/unsupported 'ghc' version detected (Cabal 3.12.1.0 supports 'ghc' version < 9.12): /usr/bin/ghc-9.12.3 is version 9.12.3" is now only shown at Info level of verbosity

Closes #9734

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