[Tooltip] Save a few bytes

[oliviertassinari]

This is a follow-up on #34289, I'm giving up on the idea of having title !== '' && title !== node an invalid value. We can be less opinionated about the best practice. Instead:

1. I believe we can shorten the logic
2. While I am at it, I'm continuing the migration to use screen as much as possible that Sebastian started. It's supposed to be simpler to work with.

[mui-bot]

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[michaldudak]

What's the rationale behind using screen in favor of render result methods?

[oliviertassinari]

What's the rationale behind using screen in favor of render result methods?

@michaldudak The rationale was that it's easier to work with, meaning when you write a new test, it's easier to access a global variable than to go up to the render() to get your helper, and then go down to use it. This problem alone could be solved by writing something like const mountingPoint = render( but we never mount two components at the same time (I assume nor will we ever need to), so why not move this even one scope further up?

@eps1lon Does it match with the value you envision?

I can revert the changes in the tests if we are not comfortable with them.

[eps1lon]

What's the rationale behind using screen in favor of render result methods?

render results will break once you introduce a Portal. screen is easier to c&p around.

[michaldudak]

👍 I'm fine with this change. My only concern is that it doesn't really fall into the "Save a few bytes" label. Could we make it a separate PR?