fix slimefun block turning into a vanilla block if there are viewers

[J3fftw1]

Description

when a slimefun block with an inventory has a viewer and gets broken it turns into a vanilla item.

Proposed changes

Changed the for loop.

Related Issues (if applicable)

https://paste.walshy.dev/pS31PJ6GnlJy

Checklist

• I have fully tested the proposed changes and promise that they will not break everything into chaos.
• I have also tested the proposed changes in combination with various popular addons and can confirm my changes do not break them.
• I have made sure that the proposed changes do not break compatibility across the supported Minecraft versions (1.16.* - 1.20.*).
• I followed the existing code standards and didn't mess up the formatting.
• I did my best to add documentation to any public classes or methods I added.
• I have added Nonnull and Nullable annotations to my methods to indicate their behaviour for null values
• I added sufficient Unit Tests to cover my code.

[github-actions]

Your Pull Request was automatically labelled as: "✨ Fix"
Thank you for contributing to this project! ❤️

[github-actions]

Slimefun preview build

A Slimefun preview build is available for testing!
Commit: 9bc350c6

https://preview-builds.walshy.dev/download/Slimefun/4101/9bc350c6

Note: This is not a supported build and is only here for the purposes of testing.
Do not run this on a live server and do not report bugs anywhere but this PR!

[JustAHuman-xD]

LGTM

[JustAHuman-xD]

I assume the update to mock Bukkit allows us to do this in testing then?

[WalshyDev]

Yep, this was implemented in like 1.19 or something of MockBukkit