Incorrect error message when sending to an address with an invalid checksum

**Describe the bug**

If you try to send to a non-lowercase address that doesn't have the right checksum/casing when using a dev network (e.g. Ganache), MM displays an error message saying that the network doesn't support ENS.

**To Reproduce (REQUIRED)**
Steps to reproduce the behavior, libraries used with version number, and/or any setup information to easily reproduce:

1. Connect MM to a ganache instance
2. Send some eth to one of your MM addresses
3. Try sending ETH to a checksummed address, but with a single char randomly changed.

**Expected behavior**

An error about the address checksum failing, being incorrect, or any other explanation, but not an ENS error.

**Browser details (please complete the following information):**
- OS: OS X
- Hardware Wallet: None
- Browser: Version 79.0.3945.130 (Official Build) (64-bit)
- MetaMask Version: 7.7.3

Reproduce the issue by connecting MetaMask 7.7.3 to Ganache and sending ETH to a checksummed address with one character changed. Trace the address-validation and error-reporting path; done means the user sees a checksum-related error instead of an ENS-support error.

Written by the indexing model from the issue text.