[ICD][Server] Bump default CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE to 3 (project-chip#42046) (project-chip#42051)

* Bump default CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE to 3

* update

* Update examples/lit-icd-app/silabs/include/CHIPProjectConfig.h



---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: yunhanw-google

examples/lit-icd-app/silabs/include/CHIPProjectConfig.h

@@ -90,6 +90,6 @@
 /**
  * @brief CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE
  *
- * Increase default(2) by 1 to account for the AppTask registering
+ * The SDK default is 3; this app adds 1 (AppTask), for a total of 4.
  */
-#define CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE 3
+#define CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE 4

src/lib/core/CHIPConfig.h

@@ -1817,10 +1817,10 @@ extern const char CHIP_NON_PRODUCTION_MARKER[];
  * @def CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE
  *
  * @brief Defines the entry iterator delegate pool size of the ICDObserver object pool in ICDManager.h.
- *        Two are used in the default implementation. Users can increase it to register more observers.
+ *        Three are used in the default implementation. Users can increase it to register more observers.
  */
 #ifndef CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE
-#define CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE 2
+#define CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE 3
 #endif
 
 /**