Out of sync map-generator/assets and resources/

[Tidwell]

Describe the bug

While @FloPinguin was investigating a boat error on the new britannia map, it was noticed that rerunning the map-generator on main did not generate the same output in resources. The full diff:

See PR: #2860

See threads in Discord:
https://discord.com/channels/1359946986937258015/1450487807242932336/1459701057826586654
https://discord.com/channels/1359946986937258015/1360078040222142564/1459696652087459882

Relevant PRs:
#2813
#2683

It looks like we are missing the resized britannia asset and updated manifest (though it could be pulled from the original PR).

The lemnos map changes look like updates were made in a PR in the output manifest but were not made in the map-generator manifest. These just need updated to what they were intended to be (theres a nation that moved i think). Im also seeing the land count change, so maybe theres something else there with islands or the source image changed?

Tagged @TsProphet94 in discord to get updated original britannia assets so we have the accurate original assets in the repo that match the resources/ output

Tagged @bijx in discord for Lemnos

To Reproduce
Steps to reproduce the behavior:

1. cd map-generator && go run .
2. cd .. && npm run format
3. git diff
4. See diffs

Expected behavior
Should be no diffs

[Tidwell]

PR for britannia: #2863

[Tidwell]

PR for lemnos: #2884

[FloPinguin]

Both PRs for both "problematic" maps merged.
Thank you for the issue :)