The File Context path for the Gitpod button is not updated when browsing the repository
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### Summary
The [File Context](https://www.gitpod.io/docs/context-urls/#file-context) path for the Gitpod button is not updated when browsing the repository.
> The file context is an extension to the repository context, in that Gitpod will check out the corresponding branch and open the respective file in an editor.
The Gitpod button was originally added in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/37985. /cc @corneliusludmann @pslaughter @rkuba @ericschurter
### Steps to reproduce
1. Enable the [Gitpod Integration](https://docs.gitlab.com/ee/integration/gitpod.html).
1. Go to [`gitlab-org/gitlab`](https://gitlab.com/gitlab-org/gitlab/-/tree/master), see Gitpod button link.
- `https://gitpod.io/#https://gitlab.com/gitlab-org/gitlab/-/tree/master/` :white_check_mark:
1. Go to the `/app` directory, see Gitpod button link.
- `https://gitpod.io/#https://gitlab.com/gitlab-org/gitlab/-/tree/master/` :x:
1. Refreshing the browser while browsing the `/app` directory properly updates the context to the following.
- `https://gitpod.io/#https://gitlab.com/gitlab-org/gitlab/-/tree/master/app` :white_check_mark:
### What is the current *bug* behavior?
The Gitpod button link does not take into account the `/app` directory.
### What is the expected *correct* behavior?
The Gitpod button link should take into account the `/app` directory.
## Proposal
Generate the URL that we pass into the Gitpod button after the user clicks, but before we send the path to Gitpod.
issue