Migrate to new shared accounts logic, and handle unavailable pricing

Previously, the pricing request was run repeatedly until success, but
if it never succeeded, then opening the plan picker would crash the UI.
We now work around that cleanly instead.

Author: pimterry

package-lock.json

@@ -44,6 +44,7 @@
     "@fortawesome/free-regular-svg-icons": "^5.12.1",
     "@fortawesome/free-solid-svg-icons": "^5.12.1",
     "@fortawesome/react-fontawesome": "^0.1.8",
+    "@httptoolkit/accounts": "^1.0.0",
     "@httptoolkit/auth0-lock": "^11.26.3",
     "@httptoolkit/httpsnippet": "^2.1.1",
     "@open-rpc/meta-schema": "^1.14.2",
@@ -87,7 +88,6 @@
     "@vx/shape": "^0.0.199",
     "ajv": "^8.12.0",
     "ajv-formats": "^2.1.1",
-    "async-mutex": "^0.1.3",
     "auth0-js": "^9.13.2",
     "base64-arraybuffer": "^0.2.0",
     "d3-scale": "^4.0.2",