Add explicit use of jest types in tsconfig.json

[kraenhansen]

Summary:

See facebook/react-native#53563 for more context.

TLDR; Since jest and @types/jest are dependencies of the app and not react-native, it makes sense to move this into the app template.
This also allow libraries (not necessarily using jest) to use @react-native/typescript-config without having to install jest or re-declare types.

Changelog:

[GENERAL] [ADDED] - Add explicit use of jest types in tsconfig.json

Test Plan:

1. Initialize the template npx @react-native-community/cli@latest init TestApp
2. Patch the tsconfig.json
3. Note how this doesn't affect the ability to use describe in source files.

[cortinico]

@robhogan could you review this one?

[kraenhansen]

The failing test seems unrelated? https://github.com/react-native-community/template/actions/runs/17855767940/job/50774340500?pr=177

[cortinico]

@kraenhansen can you rebase?

[kraenhansen]

@cortinico done 👍 (could we enable the "setting to always suggest updating branches" on this repo, for the future?)

[cortinico]

@cortinico done 👍 (could we enable the "setting to always suggest updating branches" on this repo, for the future?)

Done 👍