[Skill Bug]: azure-app-onboard, azure-upgrade reference misleading path

### Preflight Checklist

- [x] I have installed the [latest version of GitHub Copilot for Azure in VS Code](https://github.com/microsoft/GitHub-Copilot-for-Azure/releases/latest).
- [x] I have checked existing resources, including using the /help command in the chat window.
- [x] I have searched for [similar issues](https://github.com/microsoft/GitHub-Copilot-for-Azure/issues).

### Repro Steps

For example,
https://github.com/microsoft/GitHub-Copilot-for-Azure/blob/58cf519848f36ba525b51a46beb7824c054f99e3/plugins/azure-skills/skills/azure-upgrade/references/languages/java/bom-migration/bom-gradle.md?plain=1#L15

https://github.com/microsoft/GitHub-Copilot-for-Azure/blob/58cf519848f36ba525b51a46beb7824c054f99e3/plugins/azure-skills/skills/azure-app-onboard/scaffold/SKILL.md?plain=1#L109

The biggest issue is that when the skills are installed on the user's machine, the path are completely different and has no "plugin" in the path. The written path patterns reflect how the files are organized in the dev repo, not how they are organized after installation. See this on what the relative paths look like when the skills are installed.

https://github.com/microsoft/GitHub-Copilot-for-Azure/blob/58cf519848f36ba525b51a46beb7824c054f99e3/hooks/scripts/track-telemetry.ps1#L226

### Prompt

N/A

### Expected Result

N/A

### Actual Result

N/A

### Attachments

_No response_

### Regression?

_No response_

### Additional Context

_No response_

Review the references in plugins/azure-skills/skills/azure-upgrade/references/languages/java/bom-migration/bom-gradle.md and plugins/azure-skills/skills/azure-app-onboard/scaffold/SKILL.md. Compare their paths with the installed layout described by hooks/scripts/track-telemetry.ps1 around line 226. Update the path patterns to match installed skills, then verify both examples no longer include the development-only plugin prefix.

Written by the indexing model from the issue text.