When quantity value is removed data objects disappears

[cuca24]

Steps to reproduce

1. Create Quantity Value unit Data Objects -> Quantity Value
2. Add that unit to any Data object with quantity valuje type field
3. Delete Quantity Value unit from Data Objects -> Quantity Value

The objects will disappear from the element tree.
There is an error [2025-02-03T08:48:15.475202+00:00] pimcore.ERROR: Unit Inch was not found. [] []
But expected behavior is that objects would remain visible in tree. Or at least better error handling to be presented to the admin user.

[blankse]

@cuca24 I created a PR: pimcore/pimcore#18056