On Issue, "checkout topic branch" should use existing branch if already created in UI

[RupertBarrow]

trafficstars

This is similar to #4120, but not identical.

There is a feature in the UI of the website, in the right side-bar of an issue, under "Development", to create a branch for an issue.

In VS Code PR and Issue view, under "Issues > Recent Issues", when clicking on an issue then the arrow to "Start working on issue and checkout topic branch", my feature requirements are :

• [ ] if a branch has already been created for this issue, use this branch instead of creating a new one
• [ ] if creating a new branch from here, give the user to rename this branch, and attach it to the issue so that it is visible in the issue side-bar on the github website, under the "Development" section

[lucas-labs]

This one would be awesome. Or at leat let us choose from current branches isntead creating a new one as a default. So that we already created a branch from the Issue web UI, we can just select that one instead of creating a new one.

This has kept me away from the "start working on issue" functionality for a long time. Especially because I was working on a company where the branch was created for us (using the web UI) before even assigning us the issue to work on.