readAddressAsContract should not swallow errors when reading contract code

**Problem**
In the readAddressAsContract function, it’s using EthQuery to grab the contract code from a specific address, but it seems like it's catching all sorts of errors, not just the ones we want.

**Expected **
If there’s no contract at the address and an error pops up, that’s totally fine. We just set contractCode to null and move on. But if a different type of error comes up, we should be logging that to Sentry to keep track and fix it if needed.

See discussion here: https://github.com/MetaMask/metamask-extension/pull/21604/files/668054d989843814da2ee7c2fe7767a05487d703#diff-57e38278f8e09d93b0037ed8fdc648d9c9601a67854a17c454bd5b3ac1d94c3dR24

Start at the readAddressAsContract entry point and inspect how EthQuery errors are handled. Review the linked pull request discussion, then verify that only the no-contract case is converted to null while other errors are reported to Sentry.

Written by the indexing model from the issue text.