fix(rpcs): remove dead and defunct RPC endpoints for Arbitrum One (42161)

[kenny-ish]

Removes 9 Arbitrum One (chain 42161) RPC endpoints from constants/extraRpcs.js that no longer work.

I checked every Arbitrum One endpoint in the file with an eth_chainId request 4 times, about 6 hours apart (2026-10-02 08:35 to 2026-10-03 02:45 UTC). An endpoint is removed only if it failed the same way every time, and only for failures that don't depend on where the request comes from: the host doesn't resolve (confirmed with Google and Cloudflare DNS), HTTP 410, a Cloudflare origin error (52x), or an explicit invalid or disabled API key.

Rate limits, timeouts, other errors and wrong chain IDs are left alone, and so are commented-out entries. A wss:// URL on the same dead host as a removed https:// URL is removed as well.

Endpoint	Result (every check)
https://arb-mainnet-public.unifra.io	DNS NXDOMAIN (Google and Cloudflare DNS)
https://arb-rpc.keccak.io	HTTP 403: "api key required"
https://arb1.lava.build	HTTP 410: "This endpoint has been discontinued."
https://arbitrum.therpc.io	DNS no address record (Google and Cloudflare DNS)
https://endpoints.omniatech.io/v1/arbitrum/one/public	HTTP 521 (Cloudflare: origin unreachable)
https://public.stackup.sh/api/v1/node/arbitrum-one	DNS NXDOMAIN (Google and Cloudflare DNS)
https://rpc.ankr.com/arbitrum/c4cc6a...	HTTP 401: "API key disabled"
https://rpc.arb1.arbitrum.gateway.fm	DNS no address record (Google and Cloudflare DNS)
https://rpc.poolz.finance/arbitrum	DNS NXDOMAIN (Google and Cloudflare DNS)

None of these URLs are touched by other open PRs. The diff only deletes whole entries (a URL line or a complete { url, tracking, trackingDetails } object). 18 other Arbitrum One endpoints answered correctly every time and are unchanged.