Passing Server URL without protocol works for Test Connection but nor for the Web Components

[a-laurowski]

• Shopware version: 5.6.6
• PHP version: 7.2
• Expected behavior: Setting Server URL without the protocol should be detected by plugin and passed correctly to Web Components
• Actual behavior: Setting Server URL without protocol works for Test Connection functionality but on frontend we have `https://SHOPWARE_DOMAIN/factfinder/SERVER_URL which is expected behavior as the Server URL is treated as a path fragment but in result this is not consistent with the Test Connection and makes this functionality become useless
• Steps to reproduce:
• set Server URL without a protocol
• clear cache
• use suggest/searchbox on frontend