Disable postgresql flags for cardano-chain-gen:lib

cardano-chain-gen library no longer directly uses postgresql, all
queries were moved to cardana-db. Because of that, we're unable
to build cardana-chain-gen:

    cannot find -lpgcommon: No such file or directory
    cannot find -lpgport: No such file or directory
    collect2: error: ld returned 1 exit status

Remove the postgresql-specific configure flags for the
cardano-chain-gen library.

Author: sgillespie

cabal.project

@@ -11,7 +11,7 @@ repository cardano-haskell-packages
 
 index-state:
   , hackage.haskell.org 2025-08-03T21:32:16Z
-  , cardano-haskell-packages 2025-06-25T13:51:34Z
+  , cardano-haskell-packages 2025-07-30T14:13:57Z
 
 packages:
   cardano-db

config/pgpass-mainnet

@@ -1 +1 @@
-/var/run/postgresql:5432:cexplorer:*:*
+/tmp:5432:cexplorer:*:*

flake.lock

@@ -262,7 +262,7 @@
                     "-optl-Wl,-lcrypto"
                   ];
                 in {
-                  packages.cardano-chain-gen.ghcOptions = ghcOptions;
+                  packages.cardano-chain-gen.components.tests.cardano-chain-gen.ghcOptions = ghcOptions;
                   packages.cardano-db-sync.ghcOptions = ghcOptions;
                   packages.cardano-db.ghcOptions = ghcOptions;
                   packages.cardano-db-tool.ghcOptions = ghcOptions;