[nrf toup][nrfconnect] Increase ICD observer pool size

The ICDMnager observer for the DNS-SD server was silently
not registered which causes the OnICDModeChange function
to be called on change from SIT to LIT.

The root cause is that in Matter 1.5, there is
an additional observer, and we have a too small pool size to
fit the 3rd one for the DNS-SD Server.

Increase the CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE to 3 for
the Nordic platform.

Signed-off-by: Arkadiusz Balys <[email protected]>

Author: ArekBalysNordic

src/platform/nrfconnect/CHIPPlatformConfig.h

@@ -171,6 +171,10 @@
 #define CHIP_CONFIG_CRYPTO_PSA_ICD_MAX_CLIENTS 256
 #endif
 
+#ifndef CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE
+#define CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE 3
+#endif // CHIP_CONFIG_ICD_OBSERVERS_POOL_SIZE
+
 #ifndef CHIP_CONFIG_ENABLE_BDX_LOG_TRANSFER
 #ifdef CONFIG_CHIP_ENABLE_BDX_LOG_TRANSFER
 #define CHIP_CONFIG_ENABLE_BDX_LOG_TRANSFER CONFIG_CHIP_ENABLE_BDX_LOG_TRANSFER