fix(webapp): use native checkbox label semantics (#4697)

## Summary

Use native label and checkbox behavior for `CheckboxWithLabel` and
enforce `jsx-a11y/no-noninteractive-element-interactions`.

The component no longer simulates checkbox activation with click
handlers on non-interactive wrappers. Native change events now drive the
controlled checked state.

Base: [#4696](https://github.com/triggerdotdev/trigger.dev/pull/4696)