[lib] Switch to Sepolia for ENSCache unit tests

Summary:
In order to switch the tests, I actually had to recreate the same on-chain data in the Sepolia testnet that I had already created in the Goerli testnet.

I wasn't able to find a Sepolia NFT "faucet" similar to the one I had found for Goerli. I ended up having to use a slightly different one that created an NFT with an HTTP URL instead of an SVG URI.

After this change, some tests are still failing. They'll be fixed in the next diff.

Depends on D11485

Test Plan:
In combination with the next diff, I manually ran ALCHEMY_API_KEY=key yarn test utils/ens-cache.test.js and confirmed no errors resulted

Note that Buildkite CI doesn't run this particular test because we never built the plumbing to have the ALCHEMY_API_KEY accessible from there. GitHub Actions CI does run this test

Reviewers: atul, ginsu

Reviewed By: ginsu

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D11486