Refactor FocalPointPicker unit test to tsx

[alpha951]

What?

• Renamed the unit tests files for FocalPointPicker component to .tsx files.
• Added jest types dev dependency.

Why?

• To make unit tests typechecked.

How?

• Renamed the unit test files to .tsx

Testing Instructions

Testing Instructions for Keyboard

Screenshots or screencast

[github-actions]

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[github-actions]

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[alpha951]

Fixes : #60529

[alpha951]

Please review the changes @WordPress/gutenberg-components

[mirka]

👋 Hi, thanks for the PR!

The baseline success check for this task is for npm run build:package-types to pass without errors. There are some changes that need to be made in the test file for type checks to pass.

Also, we don't need to add a @types/jest dependency because they are already available (see npm ls @types/jest).

[mirka]

This was fixed by another contributor in #61373. Thank you for the attempt 🙏