Fix OSS build break: add siteId param to OSS listExitNodes

listExitNodes is resolved via the #dynamic path alias, which maps to
server/lib in the OSS build and server/private/lib in enterprise/saas.
Commit 9c18936b added a 4th siteId argument to the shared caller
(handleNewtPingRequestMessage) and to the enterprise implementation, but
not to the OSS one, so under the OSS tsconfig the call fails:

  handleNewtPingRequestMessage.ts: error TS2554: Expected 1-3 arguments,
  but got 4.

This breaks 'npx tsc --noEmit' for the OSS build (the CI 'Test with tsc'
step runs it after set:oss). Add siteId?: number to the OSS signature
for parity. It is unused in OSS since that build has no remote exit
nodes to label-filter; accepting it keeps the two #dynamic
implementations interface-compatible.

server/lib/exitNodes/exitNodes.ts

@@ -19,7 +19,11 @@ export async function verifyExitNodeOrgAccess(
 export async function listExitNodes(
     orgId: string,
     filterOnline = false,
-    noCloud = false
+    noCloud = false,
+    // Accepted for parity with the enterprise implementation (used there for
+    // site-label filtering of remote exit nodes). The OSS build has no remote
+    // exit nodes, so it is unused here.
+    siteId?: number
 ) {
     // TODO: pick which nodes to send and ping better than just all of them that are not remote
     const allExitNodes = await db