doc: release notes: added entry regarding app controlled image config

Added entry on application specific configurations of sysbuild
controlled images.
Ref: zephyrproject-rtos#51166

Signed-off-by: Torsten Rasmussen <[email protected]>

Author: tejlmand

doc/releases/release-notes-3.3.rst

@@ -523,6 +523,8 @@ Build system and infrastructure
   * Issue with board revision not being passed to sysbuild images has been
     fixed.
 
+  * Application specific configurations of sysbuild controlled images.
+
 * Userspace
 
   * Userspace option to disable using the ``relax`` linker option has been