This option is enabled by default when `strict` is set [1], so just remove
the override in src/tsconfig.json that turned it off. Also remove the
`tsconfig.no-any.json` auxilliary configuration that was used during the
migration.

Fixes https://github.com/hypothesis/client/issues/3918

[1] https://www.typescriptlang.org/tsconfig#noImplicitAny