blank screen on files tab when using gateway port instead of api port

**Describe the bug**
A clear and concise description of what the bug is.

When the address entered for the API port is instead for the gateway port (e.g. http://webui.ipfs.io.ipns.localhost:8080/) the files tab will simply result in a blank page.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to the settings tab
2. Click on change the api address to the gateway address
3. Go to the files tab
4. See blank screen

**Expected behavior**
A clear and concise description of what you expected to happen.
It should probably show an error, instead of being blank

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Desktop (please complete the following information):**
- OS: Fedora 32
- Browser: Firefox 82