Post-trial user experience improvements

### Epic

_No response_

### Description

**As a new user whose free trial has just expired**

**I want to have a clear path to subscribing**

**So that I can continue using FlowFuse**

The post-trial user experience is confusing, with not enough clear direction on how to continue using FlowFuse, bugs, misleading language, and more. This Story is to improve several elements of the post-trial user experience that led to visible friction in a survey of weeks of [post-trial session recordings.](https://docs.google.com/spreadsheets/d/1mL_BQal4bQD2oQ4MONrfIPWjZXEGWB6B6j0yfLXLzZk/edit?gid=0#gid=0)

### Which customers would this be available to

Everyone - CE/Starter/Team/Enterprise

### Acceptance Criteria

- [ ] criteria 1
- [ ] criteria 2
- [ ] criteria 3
- ...

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate