updated dark theme screenshots

build/screenshots/dark/accounts.png

build/screenshots/dark/categories.png

build/screenshots/dark/chart_1.png

build/screenshots/dark/chart_2.png

build/screenshots/dark/chart_3.png

build/screenshots/dark/chart_4.png

build/screenshots/dark/filter_1.png

build/screenshots/dark/filter_2.png

build/screenshots/dark/home.png

build/screenshots/dark/hotkeys.png

build/screenshots/dark/new_category.png

build/screenshots/dark/new_normal_transaction.png

build/screenshots/dark/new_transaction_1.png

build/screenshots/dark/new_transaction_2.png

build/screenshots/dark/new_transfer_transaction.png

build/screenshots/dark/reports.png

build/screenshots/dark/search.png

build/screenshots/dark/settings_1.png

build/screenshots/dark/settings_2.png

build/screenshots/dark/templates_1.png