Ampersand in Milestone Label isn't escaped properly in slash commands

Summary

When using the /milestone command in a comment to assign a milestone to an issue, when the milestone has an ampersand in the name the command is not processed properly. The modal displays that the command was run, however no milestone tag is ever set.

Steps to reproduce

Generate a milestone with an ampersand in the name and try and set it on an issue via the slash commands.

Example Project

https://gitlab.com/groups/gitlab-com/gl-infra/-/issues

What is the current bug behavior?

Nothing happens upon execution and display that your command has processed.

What is the expected correct behavior?

That the selected Milestone tag be added to the issue.