Spinner instad or error message when authentication flow waits

[anjo0511]

Show a localized "Authenticating..." spinner instead of briefly rendering an authentication error during OAuth SSO redirects.

What changed

• The Error page uses the error.authenticating i18n key and displays a spinner when the UI detects an OAuth/login flow.
• Added error.authenticating translations to several locale common.json files.

closes: #57981

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[guan404ming]

Could you help

1. Fix static check error
2. Attach a demo or screenshot for you change
3. Add some desciption in PR body for your change

thanks!

[guan404ming]

Looks nice, needs some update

[bugraoz93]

My stamp more on implementation and Turkish translation. I think we might need more eyes on this one

[ashb]

Agreed. Commiters: lets not merge this until we've had more eyes on the translations.

[potiuk]

Actually - can you please remove translations? We have been trying this in the past, and the flow where multiple translations are added in the PR are far less likely to "work" and "get more eyes" - that was part of the experiment I've done once. It seems that tit's way better to just add an English version - and let the translator do their translations in separate PRs - possibly "grouped" together with other translations for their language.

Our tooling and AI help is making that flow way more efficient and natural.

Revoking approval to not cause any ambiguity. I agree to delete translations

[pierrejeambrun]

PR looks good but that shouldn't be needed. I asked more information on the related issue because I'm unsure why we are observing this at the moment and if this is the appropriate fix.

[pierrejeambrun]

Closing this because it's stale. More info are required on the linked issue before we can merge this (because it really shouldn't be needed, so I suspect the root cause might be missed) . This PR looks fine and we can re-open if it appears to be the necessary fix.