registerTestTextInput property

Whether to install the flutter/textinput mock.

False on native, where Patrol drives the platform's REAL keyboard through native automation and the mock would intercept text meant for it.

True on web, where there is no native automation: nothing else installs the mock, so tester.enterText completes normally and delivers NOTHING. The field keeps its previous value and any validator on it fires, which surfaces as a form rejecting valid input rather than as a lost keystroke.

It has to be decided HERE rather than at the call site. Registering the mock inside PatrolTester.enterText is too late: by then the field has been focused and its text-input connection already opened against no mock, so the first enterText of each test still writes nothing (measured — the dialog under test stayed open on a blank required field). Deciding it at binding init puts the mock in place before anything can focus a field.