Update a test plan

Updates the provided fields of a test plan; omitted fields are left unchanged. At least one field is required.

executionMode sets the plan's stored Execution setting: parallel runs cases concurrently up to the organization's concurrency limit, sequential runs one case at a time in plan order. stopOnFailure only takes effect on sequential runs.

mobileConfig and desktopConfig set the plan's target devices and app, exactly as the plan settings page does: a triggered or scheduled run uses them, and with deviceMode: matrix every case runs on each device. Each key is replaced whole: omit it to leave the saved config unchanged, send null (or, for desktop, an empty devices list) to clear it. Local phones and desktop devices need the organization's BYOD feature. An upload or registered device from another organization, an upload that has not reached succeeded, a registered phone under the wrong platform or an upload built for the other platform is rejected with a 4xx naming the field (Device Farm devices are not platform-checked).