refactor!: keep internal tester helpers off the generated locator API

[totally-not-ai]

Summary

CheckboxGroupTester.updateSelection was public, so the annotation processor copied it onto the generated CheckboxGroupLocator. It is an internal helper that models nothing a user does, so it is now private and no longer appears on the locator API. Two unused private methods in the text field testers are also deleted.

What changed

Breaking: CheckboxGroupTester.updateSelection(Collection<String>, BiConsumer<Collection<V>, Collection<V>>) is now private, and CheckboxGroupLocator.updateSelection(...) is gone from the generated locator. Anyone who called either method directly will no longer compile. Use selectItems(...) and deselectItems(...) instead — they call the helper internally and run the usability check first.

Why it was wrong to expose it:

• It takes a BiConsumer that decides whether to add or remove items — an implementation detail, not a user action.
• It was the only generated locator method that mapped to nothing a real user does.
• It was the only public tester method there that skipped ensureComponentIsUsable().

RadioButtonGroupTester already keeps its own updateSelection private, so this makes the two testers consistent.

Also removed the unused private hasValidation() / getValidationSupport() pair from TextFieldTester and TextAreaTester. Nothing called them, so this part has no effect on users.

API Changes

com.vaadin.flow.component.checkbox.CheckboxGroupTester

// Removed
public void updateSelection(Collection<String> selection, BiConsumer<Collection<V>, Collection<V>> updater) // now private; internal helper behind selectItems/deselectItems

com.vaadin.flow.component.checkbox.CheckboxGroupLocator

// Removed
void updateSelection(Collection<String> selection, BiConsumer<Collection<V>, Collection<V>> updater) // generated delegate dropped, since the tester method is no longer public

Test summary

#	Status	What the test verifies	Why it matters
1	✅	CheckboxGroupLocator has no updateSelection method	This is the whole point of the change: the internal helper must stay off the generated locator API.
2	✅	CheckboxGroupLocator still has selectItems	Guards against the fix going too far and hiding the real user-facing methods too.
3	❗ gap	selectItems / deselectItems still work after the helper became private	Existing checkbox group tester tests cover this indirectly, but no test was added or changed here for it.

• GeneratedAggregatorsTest.locatorDoesNotDelegateInternalTesterHelpers — covers rows 1 and 2.

Deliberately untested: the deleted hasValidation() / getValidationSupport() methods in TextFieldTester and TextAreaTester. They were private and unreachable, so removing them cannot change behaviour.

[mcollovati]

Merge main and resolve conflicts. Also make the commit and the PR titles a refactor instead of chore and mark them as breaking change

[totally-not-ai]

@mcollovati Done — main is merged and the titles are updated.

Merge. One conflict, in TextAreaTester: main added clear() / clickClearButton() in the same spot this branch deleted the dead hasValidation() / getValidationSupport() pair. Resolved by keeping both new methods and dropping the dead pair. TextFieldTester and CheckboxGroupTester merged cleanly. The net diff against main is unchanged in substance: updateSelection private, the two dead private methods gone, one new locator test.

Titles. The PR title is now refactor!: keep internal tester helpers off the generated locator API, and the description carries a BREAKING CHANGE: footer naming the removed method and its replacements. Since this repo squash-merges with the PR title and body as the commit message, that is what lands on main. The branch's own commit still reads chore: — rewording it would mean force-pushing over what is already pushed here, so I left it; the squash commit is the one that ends up in the history.

Also corrected the generated-locator entry in the API-changes section, which listed a String id parameter the generated delegate never had.

Verification. Full mvn verify on the merge result: shared, junit6 (1224 tests), the CDI module and quarkus all green. Two failures in SpringPageTitleGeneratorTest (pageTitleGeneratorBean_resolvesTitleOfViewWithPageTitleValue and ...WithoutPageTitle) — these reproduce on a clean checkout of main at 897ea56 with the same expected/actual values, so they are pre-existing and unrelated to this branch. spotless:check passes.