/obj/item/stack/sheet/mineral/sandstone/thirty does not work for donate mineral

## Round ID:

5511

## Testmerges:

[#2053: 'Allows subjects of the dominion to speak to eachother' by Pontenerd at commit dd273151ea](https://github.com/BeeStation/NSV13/pull/2053)
[#2094: '[PORT] Flavor Texts/Flavour Text' by Bobbanz1 at commit 289853d343](https://github.com/BeeStation/NSV13/pull/2094)
[#2211: 'You got mail!' by bluewasabi24 at commit 42126856e8](https://github.com/BeeStation/NSV13/pull/2211)
[#2225: 'Atlas fixes' by Pontenerd at commit e6b66a4735](https://github.com/BeeStation/NSV13/pull/2225)
[#2221: '[PORT] Fixes Emissives, aswell as adds an atomized version of update_appearance' by Bobbanz1 at commit bc073f479f](https://github.com/BeeStation/NSV13/pull/2221)
[#2229: 'Fixes the manuals to make them send you to the correct page on the Wiki' by Bobbanz1 at commit 0254cfe7d3](https://github.com/BeeStation/NSV13/pull/2229)
[#2227: 'Adds multiz trunks to pipe dispensers' by benbot16 at commit 0852a03fb4](https://github.com/BeeStation/NSV13/pull/2227)
[#2236: 'Broadsides are Dead, Long Live Broadsides' by BetaCentari at commit a5a49a1c24](https://github.com/BeeStation/NSV13/pull/2236)
[#2240: 'The Return of PointyBoi: Point Harder (Finding Waldo Edition)' by Bobbanz1 at commit 7ba4b9673d](https://github.com/BeeStation/NSV13/pull/2240)
[#2234: 'Make turnstiles shock when broken and make them repairable' by Kenionatus at commit b673bb82f0](https://github.com/BeeStation/NSV13/pull/2234)
[#2233: 'Fixes border looping for large ships' by Ikalpo at commit c59bb0fd25](https://github.com/BeeStation/NSV13/pull/2233)
[#2230: 'Bug fixes and some commenting for Custom Emotes!' by Bobbanz1 at commit 59c6924c12](https://github.com/BeeStation/NSV13/pull/2230)
[#2237: 'Medicine/Synthesizer Rebalance' by BetaCentari at commit e02efbef91](https://github.com/BeeStation/NSV13/pull/2237)
[#2239: 'Makes the Wiki Uplink work in TGUI ModComp Form!' by Bobbanz1 at commit 91c7695bb7](https://github.com/BeeStation/NSV13/pull/2239)
[#2210: 'makes all food forkable' by Pontenerd at commit 8d3a076a35](https://github.com/BeeStation/NSV13/pull/2210)
[#2132: 'DLV Serendipity' by BetaCentari at commit a986e43342](https://github.com/BeeStation/NSV13/pull/2132)

## Reproduction:

delivery mission: roll donate 50u of standstone bricks
according to the gamemode controller, the objective wants 50u of /obj/item/stack/sheet/mineral/sandstone, and will not accept /obj/item/stack/sheet/mineral/sandstone/thirty, depsite that being what cargo delivers, and despite there being 50u of it in the stack

Start by searching for /obj/item/stack/sheet/mineral/sandstone/thirty and the gamemode controller's mineral-donation validation. Reproduce the delivery mission with 50u of sandstone bricks and trace why the delivered subtype is rejected. Done means the mission accepts the delivered sandstone stack when it contains the requested amount.

Written by the indexing model from the issue text.