Fix: use buildFromSdist for packages managed by haskell-flake only

[srid]

See #298 (comment)

[srid]

Reproduced,

❯ nix build github:shivaraj-bh/haskell-rust-ffi-template --override-input haskell-flake github:srid/haskell-flake
[..]
       error: attribute 'override' missing

       at /nix/store/fjvkr94j3lwca8y66zccn15rjwzqn0rd-source/pkgs/development/haskell-modules/lib/compose.nix:38:28:

           37|    */
           38|   overrideCabal = f: drv: (drv.override (args: args // {
             |                            ^
           39|     mkDerivation = drv: (args.mkDerivation drv).override f;

Tested the fix,

❯ nix build github:shivaraj-bh/haskell-rust-ffi-template --override-input haskell-flake github:srid/haskell-flake/9cb782f5338f983c6e77bbb8a573786a67492bcf
warning: not writing modified lock file of flake 'github:shivaraj-bh/haskell-rust-ffi-template':
• Updated input 'haskell-flake':
    'github:srid/haskell-flake/474fcb07635972baa325e47db84cc2195712da5a' (2024-03-28)
  → 'github:srid/haskell-flake/9cb782f5338f983c6e77bbb8a573786a67492bcf' (2024-04-22)