[FR]: Proxy settings

### Description

1. Add the ability to proxy every request to api
2. Can't find how it can be done right now
3. Idially it should be something similar to the Android version
`
System.setProperty("https.proxyHost", "x.x.x.x");
System.setProperty("https.proxyPort", "nnnn");
System.setProperty("com.google.api.client.should_use_proxy", "true");
`

### API Proposal

_No response_

### Firebase Product(s)

Database