Add basic event support for setting events

[hernanmd]

Notes

This PR needs https://github.com/pharo-project/pharo/pull/17350 to be integrated in the Pharo image

Details

Introduces the following updates:

• Get the real value when getting a setting presenter from a setting declaration.
• Announce SettingUpdated on checkboxes only if the setting effectively changed.
• Fix checkboxes items always opening with the default value instead of the real value.
• Add announcer support in StSettingPresenterItem

[jecisc]

StSettingsTrackerTest
 ✗ #testSettingUpdated (12ms)
TestFailure: Assertion failed
StSettingsTrackerTest(TestAsserter)>>assert:description:resumable:
StSettingsTrackerTest(TestAsserter)>>assert:description:
StSettingsTrackerTest(Object)>>assert:
[ : ann |
		self assert: (tracker changedSettings includes: ann) ] in StSettingsTrackerTest>>testSettingUpdated ...assert: (tracker changedSettings includes: ann)
FullBlockClosure(BlockClosure)>>cull:
[ :ann |
			numberOfAnnouncements := numberOfAnnouncements + 1.
			aBlock cull: ann ] in StSettingsTrackerTest>>when:do:
FullBlockClosure(BlockClosure)>>cull:
FullBlockClosure(BlockClosure)>>cull:cull:
[ action cull: anAnnouncement cull: announcer ] in AnnouncementSubscription(AbstractAnnouncementSubscription)>>deliver: