radicle-node: Enable e2e tests

Turns out most of these tests just run into `ulimit -n`.

pkgs/by-name/ra/radicle-node/package.nix

@@ -26,15 +26,16 @@
     darwin.apple_sdk.frameworks.Security
   ];
 
-  doCheck = with stdenv.hostPlatform; isx86_64 && isLinux;
+  doCheck = stdenv.hostPlatform.isLinux;
 
   preCheck = ''
     export PATH=$PATH:$PWD/target/${stdenv.hostPlatform.rust.rustcTargetSpec}/release
+    # Tests want to open many files.
+    ulimit -n 4096
   '';
   checkFlags = [
     "--skip=service::message::tests::test_node_announcement_validate"
     "--skip=tests::test_announcement_relay"
-    "--skip=tests::e2e"
   ];
 
   postInstall = ''