When a user changes request options in a custom action through the
console that triggers a request to the server to test webhook transform
options, and to show a preview of the result. If the action uses an
environment variable in its webhook URL, and there is no mock value for
that variable in the action's sample context then the user will see an
error. This change expands the error message to explain what caused the
error, and how to fix it.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4556
GitOrigin-RevId: 75b19bae17aac982c2bdfbd4417bd55923889f2f
f14891c64b