Checks from forks don't run

[jhkennedy]

For example: #1461

Only half(?) of the changelog updated check runs on forks, and the rest of the checks don't seem to run at all. We likely just need to add

on:
  pull_request:
    types:
      - opened
      - labeled
      - unlabeled
      - synchronize

to our workflows

[jhkennedy]

Similarly, snyk fails on forks due to missing secrets:
https://github.com/ACCESS-Cloud-Based-InSAR/hyp3/actions/runs/9689319903/job/26737394391