Fix potential crashes by using shared pointers for app data

[jacobkeeler]

Fixes #3892

This PR is ready for review.

Risk

This PR makes no API changes.

Testing Plan

Run ./test_scripts/Smoke/Resumption/005_Resumption_big_amount_of_data.lua repeatedly (listed in issue)

Summary

Use shared pointers instead of raw pointers for app data to prevent potential deallocation while reading data

Changelog

Bug Fixes

• Use shared pointers instead of raw pointers for app data to prevent potential deallocation while reading data

CLA

• [x] I have signed the CLA

[jacobkeeler]

@VjKlepikov can you verify if this fixes the issue on your end?

[VjKlepikov]

@jacobkeeler Issue is not reproduced on https://github.com/smartdevicelink/sdl_core/pull/3900/commits/e30057e19bceaeed1bc0af36ddaf18bef5f6ecc8