Git API shows incorrect remote when there's an extra push url

[alexr00]

Found while trying to fix microsoft/vscode-pull-request-github#2891

The setup:

1. Have a folder with a basic git setup with github remotes, like this:

PS D:\repos\alexr00\playground> git remote -v
origin  https://github.com/alexr00/playground.git (fetch)
origin  https://github.com/alexr00/playground.git (push)

2. Add another push remote:

PS D:\repos\alexr00\playground> git remote set-url --add origin "file:///C:\Users\alros\extraRemote"
PS D:\repos\alexr00\playground> git remote -v
origin  https://github.com/alexr00/playground.git (fetch)
origin  https://github.com/alexr00/playground.git (push)
origin  file:///C:\Users\alros\extraRemote (push)

3. Now, use the git extension API to get the remotes for this repository.
4. The git extension API specifically has a separate fetch and push url:
   

   vscode/extensions/git/src/api/git.d.ts

   Lines 64 to 65 in e3829dc

   	readonly fetchUrl?: string;
   	readonly pushUrl?: string;

   
   So I would expect those to reflect the results of git remote -v: the fetch url should be the github url, and the push url should be one of the push urls.
   In practice, both fetchUrl and pushUrl are the file url.