fix: replace the wooden floor under the standing tanks of the small cabin

[0Monet]

Checklist

Required

• I wrote the PR title in conventional commit format.
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• I linked any relevant issues using github keyword syntax so it can be closed automatically.
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Purpose of change

Replace the wooden floor under the small cabin standing tanks with outdoor terrain.

Describe the solution

Set "0" in the mapgen chemical_lab_ocu to use the same terrain as "~"

Describe alternatives you've considered

none

Additional context

Before:

After: