Switch to FetchWithContext

[bigkevmcd]

What changed?

This updates the calls to the fetcher to use the newer FetchWithContext method.

• Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps.
• Has Tests included if any functionality added or changed.
• Has an Example if the change requires configuration to use.
• Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings).
• Release notes contains the string "action required" if the change requires additional action from users switching to the new release.

For new Generators the above notes apply, with the following additional items:

• The Generator has been added to the Matrix generator's GitOpsSetNestedGenerator, this should be done by default unless there's some reason it doesn't work.
• The Generator has been added to the list of configurable Generators, if you do not, the generator cannot be enabled!
• If the Generator depends on Kubernetes resources, a Watch has been added to track changes to the resources in the controller.

Release Notes

NONE