[backport v2.12.3] Fleet GitRepos - SSH hosts with numeric ports are not allowed

[rancher-ui-project-bot]

This is a backport issue for #15397, automatically created via GitHub Actions workflow initiated by @torchiaf

Original issue body:

Setup

• Rancher UI version: v2.13-head, v2.12.2

Describe the bug

When creating GitRepos, It's not possible to assign SSH hosts with a numeric port, e.g.: git@git.apps.local:33333/fleet/fleet-local.git

To Reproduce

1. Go to Fleet -> AppBundles -> create GitRepo
2. Assign git@git.apps.local:33333/fleet/fleet-local.git to "Repository URL" field

Result

The "Next" button is disabled

Screenshots

Additional context