fixup: Ensure GetChainConfigContent includes non-primary chains

Author: maru-ava

tests/fixture/tmpnet/network.go

@@ -895,6 +895,18 @@ func (n *Network) GetChainConfigContent() (string, error) {
 			Config: marshaledFlags,
 		}
 	}
+	for _, subnet := range n.Subnets {
+		for _, chain := range subnet.Chains {
+			marshaledFlags, err := json.Marshal(chain.Flags)
+			if err != nil {
+				return "", fmt.Errorf("failed to marshal flags map for chain: %w", chain.ChainID, err)
+			}
+			chainConfigs[chain.ChainID.String()] = chains.ChainConfig{
+				Config: marshaledFlags,
+			}
+		}
+	}
+
 	marshaledChainConfigs, err := json.Marshal(chainConfigs)
 	if err != nil {
 		return "", fmt.Errorf("failed to marshal chain configs: %w", err)