Fix MaterialStorageMagnetPickup material duplication

[whatston3]

About the PR

What it says on the tin.

Calls Del over QueueDel when inserting materials into material storage. Our MaterialStorageMagnetPickup doesn't account for duplication, relying on TryInsertMaterialEntity. Problem is that it queues the entity for deletion, which'll happen before the next tick, but after other lathes check their magnets.

Why / Balance

Bug report here: https://discord.com/channels/1123826877245694004/1338300489481326593

How to test

1. Place two autolathes adjacent to each other.
2. Enable the magnet on both lathes.
3. Place a stack of steel sheets between both of the lathes where the cursor isn't highlighted.
4. The material should only be inserted into one lathe.

Media

Requirements

• I have read and am following the Pull Request and Changelog Guidelines.
• I have added media to this PR or it does not require an ingame showcase.

Breaking changes

Changelog

No real in-game effect outside of abuse prevention, no changelog this time.

[whatston3]

Alternatively, we could delete the entity in MaterialStorageMagnetPickupSystem instead and leave the material insertion as-is. Same end point, and I think only our MaterialStorageMagnetPickup system has this issue.