matter: OTA optimization release note

Added a release not to inform abouta OTA optimization
The imgage transfer time dropped by 15%

Signed-off-by: Adam Maciuga <adam.maciuga@nordicsemi.no>

Author: Adam-Maciuga

doc/nrf/releases_and_maturity/releases/release-notes-3.3.0-preview2.rst

@@ -202,6 +202,7 @@ Matter
 
 * Updated the :ref:`matter_test_event_triggers_default_test_event_triggers` section with the new Closure Control cluster test event triggers.
 * Deprecated the secure persistent storage backend enabled with the :option:`CONFIG_NCS_SAMPLE_MATTER_SECURE_STORAGE_BACKEND` Kconfig option.
+* Decreased Matter OTA image transfer time by around 15%.
 
 Matter fork
 +++++++++++