fix: updated sepolia rpc

[anshss]

Description

Replacement for Sepolia's RPC url with one from https://www.publicnode.com/ Earlier one isn't functional

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Can try to send a transaction,

    let rpc = LIT_CHAINS["sepolia"].rpcUrls[0];

    const provider = new ethers.providers.JsonRpcProvider(
        rpc
    );
    const signer = new ethers.Wallet(privateKey1, provider);

    const unsignedTransaction = {
        to: "0x291B0E3aA139b2bC9Ebd92168575b5c6bAD5236C",
        value: 2,
        gasLimit: "50000",
        gasPrice: (await signer.getGasPrice()).toHexString(),
        nonce: await signer.getTransactionCount(
            signer.getAddress()
        ),
    };

    const tx = await signer.sendTransaction(unsignedTransaction);
    const receipt = tx.wait();
    console.log(tx)

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

[CLAassistant]

All committers have signed the CLA.