X-Task-Diagnostics options should be propagated from the parent task to any new tasks spawned by that task

[dralley]

Version
Any

Describe the bug

When using X-Task-Diagnostics with the RPM "prune" API (and other APIs including import-export) which spawn sub-tasks from inside of the original "parent" task, none of the sub-tasks inherit the X-Task-Diagnostics options.

Expected behavior
X-Task-Diagnostics profiling options ought to be passed down to any child tasks spawned by the parent.