feat: add react testing library

[tobeycodes]

Problem

It is not currently possible to test React code in the React package

Summary of Changes

1. Adds React Testing Library https://github.com/testing-library/react-testing-library
2. Adds a very basic test for the useSolanaClient hook to test implementation

Fixes #97

[changeset-bot]

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Latest commit: 0b8b490

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[tobeycodes]

note: i could not find instances of this -test.*.ts pattern in existing test naming conventions so updated it to match how test files are currently named.

[tobeycodes]

note: i do not think the testing dependencies should be at the root package.json but the existing jest packages are there so continuining this pattern

[tobeycodes]

note: i believe we should only be using peer dependencies for react