[ci] Remove fortran for macos26

Author: dpiparo

.github/workflows/root-ci-config/buildconfig/mac26.txt

@@ -25,6 +25,7 @@ builtin_zeromq=ON
 builtin_zstd=ON
 check_connection=ON
 cocoa=ON
+fortran=OFF
 minuit2_omp=OFF
 pythia8=OFF
 test_distrdf_dask=ON