[Telink] multi-fabric commissioning fix (project-chip#37865)

Increased COMMON_LIBC_MALLOC_ARENA_SIZE for W91.
This fixes ecosystems sharing commissioning.
Tested on AppleHome, Tuya and GHA.

Co-authored-by: interfer <diman1436@gmail.com>

Author: s07641069

config/telink/chip-module/Kconfig.defaults

@@ -90,6 +90,7 @@ config HEAP_MEM_POOL_SIZE
 config COMMON_LIBC_MALLOC_ARENA_SIZE
     default 20716 if SOC_SERIES_RISCV_TELINK_B9X_RETENTION || (SOC_RISCV_TELINK_TL321X && ZEPHYR_VERSION_3_3)
     default 16384 if SOC_RISCV_TELINK_TL721X || (SOC_RISCV_TELINK_TL321X && !ZEPHYR_VERSION_3_3)
+    default 13568 if SOC_RISCV_TELINK_W91
     default 12288
 
 config NET_IPV6_MLD