Fix routing for 'Back' button on the 'user-b/no-share' page

[Svenstar74]

Describe the bug

The 'Back' button on the /user-b/no-share page won't bring you back to the right page.

To Reproduce

Steps to reproduce the issue:

• You start the userB's journey (enter a name, copy the link, paste it into a new tab)
• You press the button 'Next: How does ClimateMind work?'
• You press the button 'No Thanks'
• You press the button 'Back'
• The page you see now is the wrong page

Expected behavior

Instead of the page you see in the current state, it should just bring you back to the previous 'How does Cm works' page.

Task

The page with the 'Back' button is being used twice. So if you change the functionality that it works and brings you back to the 'How does Cm work?' page, you should test the second use case as well. This second use case happens at the end of the userB journey, where there's another button 'Not now'.
Bonus points if you add cypress tests, so that we will know in the future when things stop working.