Major - P3 We don't sufficiently validate `sortBy` during parsing with all window functions. Example queries that hit tassert:
Expression in `sortBy` (location 5429410):
$setWindowFields: {
sortBy: {a: {$meta: "randVal"}},
output: {b: {$max: 5, window: {range: [+3, 'unbounded']}}}
}
Descending sort (location 5429404):
$setWindowFields: {
sortBy: {a: -1},
output: {b: {$max: 5, window: {range: [+3, 'unbounded']}}}
}