Makes plastic crates actually a crate type

[SECBATON-GRIFFON]

[bugfix][consistency]

What this does

Closes #37255.
also cleans up this file by removing redundant variable declarations from supertypes.

How it was tested

spawn plastic crate, drags into and out of disposals bin.

Changelog

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• bugfix: Plastic crates now actually behave like crates in many ways, such as not letting stood up mobs inside, going into disposals bins, shuffling the contents inside, and etc.

[west3436]

Pretty sure every map has a plastic crate mapped in the cargo bay. Did you confirm every instance of the old typepath has been replaced?

[SECBATON-GRIFFON]

Pretty sure every map has a plastic crate mapped in the cargo bay. Did you confirm every instance of the old typepath has been replaced?

yep, searched "pcrate" and found absolutely nothing. that's the food crates you're thinking of. only meta had them mapped anywhere.