[@reach/tooltip] Simplify Tooltip statechart management

[Andarist]

• Use a meaningful title for the pull request. Include the name of the package modified.
• Test the change in your own code (Compile and run).
• Add or edit tests to reflect the change (Run with yarn test).
• Add or edit Storybook examples to reflect the change (Run with yarn start).
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This pull request:

• Creates a new package
• Fixes a bug in an existing package
• Adds additional features/functionality to an existing package
• Updates documentation or example code
• Other

Description

By definition, statecharts ignore events for which they don't have defined transitions on the active state node. So it seems to me this is counterproductive to guard against "undefined" transitions at the event dispatch site. The main reason for that is that whenever you want to tweak your statechart definition you'd have to tweak your transition call sites too

This was previously submitted as #176 but that PR got closed because of housekeeping purposes. I still believe this change is valid and beneficial, so I'm resubmitting this.

[Andarist]

@chancestrickland friendly 🏓