Defer the loading of Sync native lib to when necesasry

[aitorvs]

Task/Issue URL: https://app.asana.com/0/488551667048375/1207535395708800/f

Description

Defer loading the sync native library to when it's actually used. This avoids:

• loading the library on process launch when not necessary
• loading the library at all for the :vpn process

Steps to test this PR

Filter logcat by Loading native SYNC library

Test

• [x] build from branch and fresh install/launch app
• [x] verify Loading native SYNC library is not logged
• [x] enable sync
• [x] verify Loading native SYNC library is logged
• [x] enable AppTP
• [x] verify Loading native SYNC library is not logged when AppTP is enabled
• [x] force closed the app (adb shell am force-stop com.duckduckgo.mobile.android.debug)
• [x] re-launch app
• [x] verify Loading native SYNC library is shown only once, when the main process is created (not when AppTP is enabled aka :vpn process is created)

Note: if you repeat the test in develop the Loading native SYNC library shows every time both the main and :vpn processes are created, irregardless of whether sync is enabled or not

[aitorvs]

• #4647 👈
• develop

This stack of pull requests is managed by Graphite. Learn more about stacking.

Join @aitorvs and the rest of your teammates on Graphite