chore(test): Move the wireguard key generation in the integration tests to the test script to make the derivations deterministc while keeping random keys

tests/integration/rp-key-sync.nix

@@ -32,8 +32,8 @@ let
           description = "network address of the host that runs rosenpass";
         };
 
-        peerPubkey = lib.mkOption {
-          type = lib.types.str;
+        peerPubkeyFile = lib.mkOption {
+          type = lib.types.path;
           description = "Public key of wireguard peer";
         };
 
@@ -73,10 +73,11 @@ in
         # The script downloads the key generated by rosenpass from the key exchange node and sets it as the preshared key for the specified wireguard peer.
         script = ''
           set -euo pipefail
+          PEER_PUB_KEY=$(cat ${instanceCfg.peerPubkeyFile})
           ${pkgs.openssh}/bin/ssh ${instanceCfg.rpHost} "cat ${instanceCfg.remoteKeyPath}" \
             | ${pkgs.wireguard-tools}/bin/wg \
               set ${instanceCfg.wgInterface} \
-              peer ${instanceCfg.peerPubkey} \
+              peer $PEER_PUB_KEY \
               endpoint ${instanceCfg.endpoint} \
               allowed-ips ${instanceCfg.allowedIps} \
               preshared-key /dev/stdin