Conflicting messages regarding RRM status when awaiting approval

## Bug Description

If a user is awaiting approval for RRM, which can take up to two weeks, the messaging regarding "Complete setup" in RRM settings, or "Complete publication setup" on the dashboard may be confusing, as setup is already complete. In addition, clicking on the button from the RRM settings page directs a user to the Site Kit dashboard.

There are a couple of improvements here, which could potentially be split into separate issues:

### Improvement one:

Change the button text below from "**Complete setup**" to "**Back to dashboard**" as that's what the button does, as opposed to completing setup.

### Improvement two:

In the case of RRM initial set up is complete, but a user is awaiting approval. change the below button text from "Complete publication setup" to "Go to publisher center" or "Visit Reader Revenue Manager".

I'm aware also that it may be hard to determine or distinguish the status from the API, which limits the exact messaging.

## Steps to reproduce

1. On a new site, set up RRM (a new publication) within Site Kit. You'll be directed to the RRM platfrom in a new tab from Site Kit in order to do so.
2. After setup is complete on the RRM side, revisit the Site Kit settings tab
3. A message will appear regarding competing setup. Clicking on that directs you back to the Site Kit dashboard
4. On the Site Kit dashboard, a notice appears suggesting users complete setup. This isn't required, the publication is awaiting approval.

## Recording of experience

https://github.com/user-attachments/assets/0eeb5b26-cf33-4cc7-ad0b-6185ba8ceecd

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## Acceptance criteria

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## Implementation Brief

* [ ]

### Test Coverage

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## QA Brief

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## Changelog entry

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Start by reproducing the flow through the RRM settings page and Site Kit dashboard described in the issue, including the awaiting-approval state. Trace how that state is obtained and how each button label and destination is selected; done means the messages no longer imply setup is incomplete and each button leads to its intended destination.

Written by the indexing model from the issue text.