Task: Replace `mocha` with `vitest` for SVelte tests

[stricklandrbls]

Task: Replace mocha with vitest for Svelte Tests

Description  

mocha as the testsuite is no longer compatible for executing tests when the updated Svelte 5 runes exist within a testable source.

Using vitest would be a complete, and compatible, solution as it is used alongside vite. I feel that this would be the best solution given that vite is now being used as a packaging dependency.

Acceptance Criteria  

vitest is successfully replaced for mocha/chai and all of the SVelte tests that exist and can execute while accurately reporting test case results.

Additional Information

I have tested this locally and all of the test files execute with vitest, even the non Svelte files.
Update
I originally had all tests executing and reporting correct results but upon inspecting under the hood of the native VSCode Test Explorer I found that it was smart enough to pull in mocha to run those tests within the ./src/tests/ directory.

vitest does not have to capability to provide the VSCode API due runtime dependency issues. mocha will still have to be used for those tests