UI: Fix notification screen light/dark theme handling and UI coherency

[RemIsMyWaifuu]

copied from #211

Description: Notifications screen was merged during the last sprint without taking into account light/dark theme and UI coherency across the application.

Acceptance Criteria:

• Notifications screen should comply with the dark/light theme in terms of contrast and text.
• Top bar should be the same as other screens

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
62.5% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud