feat: Add L2scan to chain explorers

[admin-unifra]

Add L2scan (Arb One) explorer to the chain explorers page.

[cla-bot]

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Name	Status	Preview	Updated (UTC)
arbitrum-docs	✅ Ready (Inspect)	Visit Preview	Nov 26, 2024 3:47am

[admin-unifra]

@anegg0 pls review again. We have signed the CLA.

[hkalodner]

@cla-bot check

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[admin-unifra]

@hkalodner please review

[anegg0]

LGTM

[anegg0]

Hi @admin-unifra, and apologies for the slow processing. Can you please update your fork and push to this PR?
We'll be able to merge, then.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[admin-unifra]

updated.