release
Let one quarantined proposition back into use.
contextId is an access-control bound and is checked before anything is written: a proposition belonging to another context answers null and is left exactly as it was.
Releasing twice is safe. The second call finds a proposition that is no longer quarantined and answers null without writing.
Return
Where the proposition stands after the release, or null when no proposition in that context has that id, or when the one that does is not quarantined.
Parameters
context
The context the proposition must belong to.
proposition
The proposition to release.
Throws
if either identifier is blank.