[Chore] Reduce dependabot nags on angular sample app

[gavinbarron]

Currently we have a package-lock file comited for the angular sample app. This leads to several dependabot chores each time we ship a new version of mgt.

Removing the file from the repo will smooth out this work

[ghost]

Hello gavinbarron, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌