Reduce friction in RRM onboarding

## Feature Description

Originally raised during bug bash [here](https://app.asana.com/1/8468971550303/project/1207894970935603/task/1208035131189745?focus=true).

The subtle notification when setting up the Reader Revenue Manager module does not feel user-friendly. It adds an additional step that is confusing for the user.

This messaging is also later shown in the setup success notification, and in the module's settings.

Sigal [suggested](https://www.figma.com/design/f2AFGUqfH8rqi9BpJAwhHi/Reader-Revenue-Manager?node-id=2431-22410&m=dev) removing the suble notification and replace it with a textual message:

We'll need to double-check the copy with Mariya before proceeding.

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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 locating the Reader Revenue Manager onboarding flow, setup success notification, and module settings UI where the messaging appears. Confirm the replacement copy with Mariya, then verify that the subtle notification is removed and the approved textual message appears consistently across all three surfaces.

Written by the indexing model from the issue text.