Apply the same security policy checks in ResolveCanvas as we do in GetResource. Without this, the ResolveCanvas returns metadata about metrics views and dimensions/measures that will fail when queried for the current user.

Closes https://linear.app/rilldata/issue/PLAT-164/sec-policy-exclude-not-working-on-canvas

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!