aio app pack: handle errors from pre-pack hook

[sangeetha5491]

Describe the bug When there is an error in the pre-pack hooks, aio app pack continues to ignore the error and package the app. The app needs to abort packaging when an error is reported from a pre-pack hook

To Reproduce Steps to reproduce the behavior:

1. Check out https://github.com/adobe/aio-cli-plugin-events/pull/81
2. link to aio cli
3. run aio app pack on an existing app with event registrations with invalid events of interest
4. Run aio app pack

Expected behavior Error in pre-pack hook should abort the packaging of the app via aio app pack

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context Add any other context about the problem here.

[aiojbot]

JIRA issue created: https://jira.corp.adobe.com/browse/ACNA-2556

[shazron]

Closed via https://github.com/adobe/aio-cli-plugin-app/pull/727