Remove welsh feature flag

[thomasiles]

Remove the Welsh feature flag from admin

Trello card: https://trello.com/c/gI4COCYo/2863-remove-welsh-feature-flag

Remove all uses of the feature flag and ignore the column.

The settings still need to be removed from the deploy repository but this is the first step to stop using it.

All welsh features should be fully enabled in all environments.

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

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[DavidBiddle]

Really nicely broken up and documented 🎉