update campaign builder images

[fakela]

Description

Updated screenshots for the campaign builder documentation to match the current Mautic UI.

Linked issue

Closes #468

Screenshots or screen recordings

[adiati98]

Thank you for your PR, @fakela! ✨

This looks great so far. But I have a few things for you to address here:

1. Looking at the UI images, these aren't from Mautic 5. I believe these are Mautic 7?

   Can you please rebase this PR and point it to the right base branch? Currently, your PR is pointing to 5.2. You can close and create a new PR if it's easier for you. 🙂

2. As we want to maintain consistency, please rename the files using underscore. For example: campaign_events.png. That said, you also need to fix the name within the RST file: https://github.com/mautic/user-documentation/blob/5.2/docs/campaigns/campaign_builder.rst

3. Please edit your PR description. As the changes here are for branch 7, it should only close issue #468. Other issues are for branch 5.2 and 6.0.

Please let me know if you have questions or need help. Thanks!

[adiati98]

Can you please retake the screenshot to include the copy icon button on hover state, like the existing?

[adiati98]

I've cherry-picked this in #633. Therefore, I'm closing this PR.

Thank you for the contribution! ✨