Fix lint and tests

[dgreif]

The main branch hasn't been updated in quite some time, and the test/lint scripts currently fail.

• Updated test dependencies
• Updated package-lock.json to latest format
• Fixed tests by running with concurrency: 1
• Added mocha types as a dev dependency

[Copilot]

Pull request overview

This PR fixes failing test and lint scripts in the main branch by updating test dependencies and configuration. The changes modernize the testing setup and resolve compatibility issues.

Changes:

• Updated test runner configuration to run tests sequentially and filter console noise
• Updated test dependencies to latest compatible versions
• Added TypeScript types for Mocha test framework

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
web-test-runner.config.js	Added concurrency control, browser log filtering, and formatting fix
package.json	Updated @open-wc/testing and @web/test-runner versions, added @types/mocha

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