test: microk8s wait ready timeout

[yanksyoon]

Applicable spec:

Overview

• Add timeout to microk8s setup script

Rationale

• Due to infra issues, this does not timeout and continues to hold the runner for 6+ hours

Juju Events Changes

Module Changes

Library Changes

Checklist

• The charm style guide was applied.
• The contributing guide was applied.
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation for charmhub is updated.
• The PR is tagged with appropriate label (urgent, trivial, complex).
• The changelog is updated with changes that affects the users of the charm.
• The application version number is updated in github-runner-manager/pyproject.toml.

No user facing changes.