.github/workflows: fix duplicated build target in Wasm action

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

.github/workflows/cross-wasm.yml

@@ -29,7 +29,7 @@ jobs:
       env:
         GOOS: js
         GOARCH: wasm
-      run: go build ./cmd/tailscale/cli ./ipn/... ./wgengine/... ./net/... ./safesocket ./types/... ./wgengine/...
+      run: go build ./cmd/tailscale/cli ./ipn/... ./net/... ./safesocket ./types/... ./wgengine/...
 
     - uses: k0kubun/action-slack@v2.0.0
       with: