Queries like

[{$project: {$meta: "textScore"}}]

return a failure indicating that "the query requires text score metadata, but it is not available".

However, a query like

[{$match: {$text: <>}}, {$group: {_id: null}}, {$project: {$meta: "textScore"}}]

succeeds, even though the "textScore" is not available since the $group destroys per-document metadata.

DepsTracker already tracks which stages in a pipeline will preserve or destroy metadata, so we should account for that when deciding whether or not to return an error.