Adds an accessibility live region to the camera/mic privacy chip

This change will cause screen readers to produce non-disruptive feedback
upon the initial appearance of the privacy indicator dot, and ensures
updates from the dot are throttled to 10 seconds, ensuring duplicate
feedback is not provided to users as the indicator animates from chip to
smaller dot.

This change does not impact focusability of the chip with screen
readers.

(Includes ktfmt changes for OngoingPrivacyChip.kt)

Bug: 197201744
Flag: com.android.systemui.privacy_dot_live_region
Test: Manual - tested extensively with TalkBack using Camera & Recorder
Change-Id: Iccc1b09fb29ec33e099c9b6f1957f7a488038a9c