fix: use pre-built binary instead of go run in e2e tests (#16236)

Using `go run` inside of a test is fragile, because it means we have to
wait for `go` to compile the binary while also constrained on resources
by the fact that Playwright and coderd are already running. We should
instead compile a coder binary for the current platform before the tests
and use it directly.

.github/workflows/ci.yaml

@@ -704,6 +704,9 @@ jobs:
       - run: make gen/mark-fresh
         name: make gen
 
+      - run: make site/e2e/bin/coder
+        name: make coder
+
       - run: pnpm build
         env:
           NODE_OPTIONS: ${{ github.repository_owner == 'coder' && '--max_old_space_size=8192' || '' }}