seyren: deprecate phases (#131137)

pkgs/servers/monitoring/seyren/default.nix

···
     sha256 = "1fixij04n8hgmaj8kw8i6vclwyd6n94x0n6ify73ynm6dfv8g37x";
   };
 
-  phases = ["installPhase"];
+  dontUnpack = true;
 
   nativeBuildInputs = [ makeWrapper ];
   buildInputs = [ jre ];