chore: Adjust channels and revisions for 3.0 track

[mmkay]

Issue

Documentation had some outdated links or links that pointed at the 2 track. For 3.0, we want to update them to point at the LTS track.

Solution

Update references to actual charms and revisions (I tested on candidate as stable isn't there yet)

Checklist

• I have added or updated relevant documentation.
• PR title makes an appropriate release note and follows conventional commits syntax.
• Merge target is the correct branch, and relevant tandem backport PRs opened.
• This PR has Terraform product changes and appropriate lifecycle args and moved blocks were added to the terraform/*/upgrades.tf file(s).
• This PR has breaking changes to the product API(s) and I have created an issue in SolQA pipelines to address this.

Context

Probably needs to be merged once we release the stable track and after #381.

Testing Instructions

Upgrade Notes

[mmkay]

I think we'll also need roughly the same set of changes on main, but we might want to point at dev where we did earlier.