[i18n:eu] Add Euskara language support

[darkwing]

Superecedes https://github.com/MetaMask/metamask-extension/pull/12063 to fix lint.

[github-actions[bot]]

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[metamaskbot]

Builds ready [4bc5cab]

• builds: chrome, firefox, opera
• builds (beta): chrome, firefox, opera
• builds (flask): chrome, firefox, opera
• build viz: Build System
• code coverage: Report
• storybook: Storybook
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8
  • common: 0, 1, 2, 3
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • phishing-detect: phishing-detect
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 2, 3, 4, 5

Page Load Metrics (645 ± 19 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	529	721	643	41	19
		domContentLoaded	516	723	643	45	21
		load	546	724	645	39	19
		domInteractive	516	723	643	45	21

highlights:

storybook

• ui/pages/confirm-add-suggested-token/confirm-add-suggested-token.stories.js
• ui/pages/confirm-approve/confirm-approve.stories.js
• ui/pages/confirm-deploy-contract/confirm-deploy-contract.stories.js
• ui/pages/confirm-encryption-public-key/confirm-encryption-public-key.stories.js
• ui/pages/confirm-import-token/confirm-import-token.stories.js
• ui/pages/confirm-send-ether/confirm-send-ether.stories.js
• ui/pages/confirm-token-transaction-base/confirm-token-transaction-base.stories.js
• ui/pages/settings/settings.stories.js

[mcmire]

Should probably wait until #13206 is merged before merging this.

[jpuri]

Seems #13206 is merged.

But I am not sure if we should add this language as it is not supported by crowdin and will be hard to maintain.

[mcmire]

@jpuri I think it's okay to have languages not supported by Crowdin. That means that the community will have to maintain them, but I think that's fine. Also, this language shouldn't conflict with any PRs Crowdin gives us. Agree/disagree?