Fill the module cache before a hosted go work pin

The go work vendor test pins a shared module with hosted mode from the
workspace root on a fresh machine. Hosted mode reads which version the
workspace selects from the module graph in the module cache and writes
nothing while it is empty, so the test now downloads the module first,
as an earlier build would have.

Assisted-by: Claude Code:claude-opus-5-5

Author: mikolalysenko

crates/socket-patch-cli/tests/e2e_golang_workspace_build.rs

@@ -1484,6 +1484,7 @@ fn go_work_vendor_records_the_go_work_replace() {
             assert_eq!(code, 0, "{env}\n{stderr}");
             env
         } else {
+            warm(tmp.path(), &m, &w.proxy, &[(UMOD, UVER)]);
             let (code, env, stderr) = w.api.get(&w.root, &m.modcache, &[]);
             assert_eq!(code, 0, "{env}\n{stderr}");
             env