Cached responses cause test failures

[tvsbrent]

Describe the bug

When the plugin is in record mode, any request that could be cached will return a 304 due to the default browser behavior. If the test is run multiple times in the same session, this will result in errors in subsequent test runs in the same session.

To Reproduce

1. Open up the Sandbox app spec in record-only mode.
2. Make sure "Disable caching" is not selected in the "Network" panel of dev tools.
3. Run the test once.
4. It passes.
5. Run the test again.
6. It fails.

Expected behavior
Instead of dropping 3xx responses or throwing an error, the plugin should see if there is a response recorded for that request and return that to the browser, even if the plugin is in record only mode.

Screenshots
n/a

Environment

• OS: n/a
• Cypress Version: n/a
• Browser: n/a
• Browser Version: n/a

Additional context
n/a