fix: remove cross-fetch

[PhearZero]

ℹ️ Overview

With the End of Life of Node 16 and engine set to >=18, we can safely use native fetch.

Consumers targeting ie11 or other engines can handle the fetch pollyfill.

📝 Issues

Fixes #823
Relates to #831

[nullun]

Just want to confirm that this PR fixes #823 and I'll close my revert (#831).

[PhearZero]

Just want to confirm that this PR fixes #823 and I'll close my revert (#831).

@nullun deployed an example with the following dependency in package.json:

{
  "algosdk": "github:PhearZero/js-algorand-sdk#fix/cross-fetch"
}

And the current render of getTransactionParams : https://wrangler-test.phearzero.workers.dev/

[jasonpaulos]

Great work, happy to remove this dependency