[QA] "Additional Gas" field is shown when route does not support sending additional gas

[tsadovska]

Describe the current behavior in detail

Checked on Netlify with following config.

Steps:

1. Select Arbitrum network and ETH token in "From" section (MetaMask wallet auto-connects)
2. Select Ethereum network and ETH token in "To" section (MetaMask wallet auto-connects)
3. Select Mayan route
4. Click on "Review transaction" button
5. Check if slider and "Additional Gas" field are displayed

Actual result: Slider is not displayed, but "Additional Gas" field is displayed.
Expected result: Slider and "Additional Gas" field are not displayed.

Notes/ Attachments

Tested OK on https://portalbridge.com/.