[EPIC] Palette tags

[jamesgorrie]

We need to investigate where we are with palette tags. There was quite a lot of work done here #4796.

Replicating the task list from there:

- [ ] https://github.com/guardian/dotcom-rendering/issues/4792
- [ ] https://github.com/guardian/dotcom-rendering/issues/4794
- [ ] https://github.com/guardian/dotcom-rendering/issues/4795

[ioannakok]

These are old tickets and most likely things have been fixed. We can test everything looks as expected in all the palettes though. Steps:

1. Go to: https://fronts.code.dev-gutools.co.uk/editorial/config in /break-this-front front Parisa Test container
2. You can see how it looks here: https://m.code.dev-theguardian.com/break-this-front
3. Add a Palette tag (e.g. SombreAltPalette), click "Save container". No need to test tags that do not have the Palette suffix.

4. Compare frontend (https://m.code.dev-theguardian.com/break-this-front?dcr=false) with DCR version (https://m.code.dev-theguardian.com/break-this-front?dcr=true)

[ParisaTork]

Control (no tags) looks good and we have relative parity between frontend and DCR (Frontend has 1 coloured headline and DCR has comments):

Frontend:

DCR:

Will test all tags individually in due course.