[Data masking] Suspend useFragment when a deferred fragment is pending

[jerelmiller]

Create the detection mechanism to determine if/when a fragment is pending and suspend the component.

NOTE: This work does not include checking the source of the query to see if it originated from a suspenseful hook. This is captured in a separate issue.

[jerelmiller]

This won't be part of the initial data masking release but will be introduced in a future version. I'm moving it out of the milestone for now.