Remove official support for versions of React 17 and under for CT Testing and make cypress/react18 the cypress/react package (deprecate cypress/react18)

[AtofStryker]

What would you like?

Currently, we have two react CT packages inside cypress core, react and react18. react supports versions of react 17 and down, where as the react18 harness supports react18. With react 19 being in release candidate stage and the test harness from react18 needing little changes, we likely want to remove official support for react17 inside cypress/react and make react18 the cypress/react package, which would support react 18 and 19. Users who are on older versions of react can download older versions of the test harness. This would also remove the react18 package

Why is this needed?

This allows us to more easily maintain our npm packages by rolling forward with more recent versions of component testing frameworks as well as help improve our process around npm package maintenance.

Other

No response

[AtofStryker]

this will also apply to @cypress/react19 since both are duplicate copies of the @cypress/react18 test harness

[AtofStryker]

blocked by #30511