Improve some layout

android/gradle.properties

assets/translations/en.json

assets/translations/fr.json

fastlane/metadata/android/en-US/changelogs/21.txt

fastlane/metadata/android/fr-FR/changelogs/21.txt

lib/ui/screens/main_screen.dart

lib/ui/widgets/main_screen/counts_by_day_card.dart

lib/ui/widgets/main_screen/counts_by_hour_card.dart

lib/ui/widgets/main_screen/discoveries_card.dart

lib/ui/widgets/main_screen/statistics_card.dart

lib/ui/widgets/main_screen/statistics_content.dart

lib/ui/widgets/main_screen/timeline_card.dart

pubspec.yaml