Handle empty repeated group header.

IMPORTANT: All PRs must be linked to an issue (except for extremely trivial and straightforward changes).

Fixes #726

Description In paginated layout, empty repeated group header was shown.

issue : It was creating empty answer component for repeated group item while packing repeated group header. fix :

Alternative(s) considered Have you considered any alternatives? And if so, why have you chosen the approach in this PR?

Type Choose one: (Bug fix)

Screenshots (if applicable)

Checklist

[x] I have read and acknowledged the Code of conduct.
[x] I have read the Contributing page.
[x] I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
[x] I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
[x] I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
[x] I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
[x] I have built and run the demo app(s) to verify my change fixes the issue and/or does not break the demo app(s).

google / android-fhir