[q] Updater: Adapt displayVersion to show proper versioning

Description

[q] Updater: Adapt displayVersion to show proper versioning

Issue(s)

e/backlog#5056 (closed)

Test environment

These are the steps to reproduce the said crash:

• Install https://gitlab.e.foundation/e/priv/os/build/-/jobs/289064/artifacts/file/zips/FP3/e-1.0-alpha.2-q-20220413178210-stable-FP3.zip
• Enable Settings > Developer Options > Connect to /e/OS test channel
• Check for updates
• Start Installing Apr 28 2022 update
• Once 25 MB is downloaded, hit Pause.
• Reboot the phone
• Opening Updater app crashes.

Test procedures

• Follow Test environment
• Download Updater-q.apk, which was built against this branch
• adb install Updater-q.apk
• Crash no longer happens

Technical details

• Preversion was not initialized, in this scenario and leads to a null object reference
• Crash introduced with the reverted commit in the MR.

Check list

• Self review
• Test procedure explained
• Tested on fresh install
• Tested applied as an update
• License
• Internal documentation
• User documentation