[r] Updater: Adapt displayVersion to show proper versioning

Description

[r] Updater: Adapt displayVersion to show proper versioning

Issue(s)

e/backlog#5056 (closed)

Test environment

• Install https://gitlab.e.foundation/e/priv/os/build/-/jobs/289058/artifacts/file/zips/FP4/e-1.0-alpha.2-r-20220413178209-stable-FP4.zip
• Enable Settings > Developer Options > Connect to /e/OS test channel
• Check for updates

Test procedures

• Download Updater-r.apk, built against this branch.
• adb install Updater-r.apk
• Check for updates
• Notice the changes shown in the screenshot

Screenshots

Click to expand

Desc.	Screenshot
Before 1
After 1
After 2

Check list

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