choose_merge_request does not select correct MR if there are several MRs into different target branches

[jakubbortlik]

Prerequisites

• [x] I'm on the latest version of the plugin
• [x] I've installed the required dependencies
• [x] I've run :h gitlab.nvim.troubleshooting and followed the steps there

Setup Configuration and Environment

n/a

Bug Description

The choose_merge_request action only chooses the source branch, but it always selects the same MR, even if I select different MRs that have different target branches.

I admit that this is a somewhat artificial use case -- I've never really seen MRs for the same feature branch but into different target branches, but I use this scenario in testing gitlab.nvim and some users might actually encounter this in real work.

Reproduction Steps

1. Create a feature branch
2. Create multiple MRs into different target branches
3. Run choose_merge_request for all the MRs

Expected behaviour

When I choose a MR, the correct feature as well as target branch gets selected.