Dispose Process properly in a few areas where this was missing

[nzdev]

Prerequisites

• I have added steps to test this contribution in the description below

If there's an existing issue for this PR then this fixes

Description

Prevent leaks by disposing Process instance.

[umbrabot]

Hi there @nzdev, thank you for this contribution! 👍

While we wait for one of the Core Collaborators team to have a look at your work, we wanted to let you know about that we have a checklist for some of the things we will consider during review:

• It's clear what problem this is solving, there's a connected issue or a description of what the changes do and how to test them
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[nul800sebastiaan]

Thanks @nzdev! 👍