Adjust device time test setting (DEV)

[d4rken]

Instead of faking the "disable-device-time-check" which won't work for SafetyNet,
we now fake the time offset to be within the acceptable delta.

Testing

• Check that this can't become active in production, and that the tests cover this.
• Check that you can now time travel and do and can perform a "casual" verification via the data donation test menu

[ralfgehrer]

When activating fake time and traveling one day into the future, I receive the following exception on the "Casual" SafetyNet Report
SafetyNetException: TIME_SINCE_ONBOARDING_UNVERIFIED: Time since first reliable timestamp <24h

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

80.0% Coverage
0.0% Duplication

[ralfgehrer]

Clarified with @d4rken.

• Launch app
• check test menu --> Remote config - isDeviceTimeCorrec should be true
• enable fake time
• travel > 24h
• check SafetyNet Report "Casually" --> Requirements passed

[LukasLechnerDev]

• Device has correct time
• Reset App
• Do Onboarding
• TestMenu: Create SafetyNet Report
  => casual verification fails with "Time since first reliable timestamp < 24h"

=====

• Enable "Fake correct device time"
• time travel 24h into the future
• TestMenu: Create SafetyNet Report
  => casual verification: "Requirements passed"

=====

• time travel only 23h in the future
• TestMenu: Create SafetyNet Report
  => casual verification fails with "Time since first reliable timestamp < 24h"

=> Works as expected.

• Tests also look good and verify that the time can't be faked in production builds.
• One Suggestion would be to describe the new switch a bit better in the Developer Menu. e.g. by adding "This allows time travelling while still getting positive device time checks" or something like that