[BubbleRelativeDuration](https://tc39.es/proposal-temporal/#sec-temporal-bubblerelativeduration) currently assumes it can only be called with [date units](https://tc39.es/proposal-temporal/#sec-temporal-units), but it can actually also be called with non-date units. See the test case at <https://bugzilla.mozilla.org/show_bug.cgi?id=1971346>.