app/testcase: Increase audio_utc stack size
audio_utc need more stack size.
#define TC_ARASTORAGE_STACK 4096
#endif
#if defined(CONFIG_EXAMPLES_TESTCASE_AUDIO_UTC) || defined(CONFIG_EXAMPLES_TESTCASE_AUDIO_ITC)
-#define TC_AUDIO_STACK 2048
+#define TC_AUDIO_STACK 4096
#endif
#if defined(CONFIG_EXAMPLES_TESTCASE_DM_UTC) || defined(CONFIG_EXAMPLES_TESTCASE_DM_ITC)
#define TC_DM_STACK 2048
