Summary: This PR fixes the unaligned checkbox in the Doctor modal (I have based the solution of the Settings modal code) and also replaces deprecated components `FlexRow` and `FlexColumn` in Settings modal. ## Changelog * fix checkbox placement in the Doctor modal footer Pull Request resolved: https://github.com/facebook/flipper/pull/3331 Test Plan: The change has been testes by running the desktop Flipper app locally from source. ## Preview (before & after) <img width="596" alt="Screenshot 2022-01-23 at 16 01 48" src="https://user-images.githubusercontent.com/719641/150685091-ce494847-eea6-4263-900a-2b5541d3d897.png"> <img width="596" alt="Screenshot 2022-01-23 at 16 01 44" src="https://user-images.githubusercontent.com/719641/150685096-29723d14-6cfc-42aa-9564-431a61b1061d.png"> Reviewed By: aigoncharov Differential Revision: D33738683 Pulled By: lblasa fbshipit-source-id: 900657d6cb095d6d32dd412205e714a46e64a564
flipper-ui-core (TBD)
Flipper's UI, agnostic of Electron vs Browser.