HS: fetch response unwrap + do-not-throw + dot-prop + JSON coerce (+19 tests)

tests/hs-run-filtered.js

@@ -652,6 +652,8 @@ const _fetchScripts = {
       { "/test": { networkError: true } },
   "triggers an event just before fetching":
       { "/test": { status: 200, body: "yay", contentType: "text/html" } },
+  "can do a simple fetch w/ a custom conversion":
+      { "/test": { status: 200, body: "1.2" } },
 };
 function _mockFetch(url) {
   const scriptRoutes = _fetchScripts[globalThis.__currentHsTestName];