Test an HTTP action with a real request

Requires actions:http:execute. This makes a REAL HTTP request to the configured endpoint and can change external data. Only use on an explicit test request. Never retry automatically: a repeated request is a new invocation and may repeat side effects. Preserves existing duplicate protection, receipts and diagnostics; reconcile an uncertain result before a deliberate new invocation. Other families return ACTION_OPERATION_NOT_SUPPORTED. An invocation failure may return HTTP 200 with ok:false. Write-capable tests require confirmExternalEffects=true and the current configurationVersion. Obtain explicit user confirmation for this individual real HTTP request; never infer consent from management scopes or retry automatically. Missing/stale confirmation returns HTTP_TEST_CONFIRMATION_REQUIRED (403) before dispatch. Read-only tests do not require consent. This confirmation requirement also applies to deprecated Tools write tests: older clients must explicitly confirm and send configurationVersion. Explicit new Off mode returns ACTION_INACTIVE (403); historical inactive definitions without an explicit mode retain direct-test eligibility. No test endpoint for Sheets or collection actions; use Playground.