hide theme selector in prod (#2671)

...nsactions-creates-a-test-transaction-1-chromium-linux.png

...nsactions-creates-a-test-transaction-2-chromium-linux.png

...nsactions-creates-a-test-transaction-3-chromium-linux.png

...ons-filters-transactions-by-category-7-chromium-linux.png

...ons-filters-transactions-by-category-8-chromium-linux.png

...ons-filters-transactions-by-category-9-chromium-linux.png

...actions-filters-transactions-by-date-7-chromium-linux.png

...actions-filters-transactions-by-date-8-chromium-linux.png

...actions-filters-transactions-by-date-9-chromium-linux.png

packages/desktop-client/playwright.config.js

packages/desktop-client/src/components/Titlebar.tsx

upcoming-release-notes/2671.md