Enable tls credential shell

Getting weird results on the ESP32-S3 though:

```plaintext
uart:~$ cred list
1001,CA,ERROR,-134
1002,CA,ERROR,-134
1003,CA,ERROR,-134
```

Author: noahp

prj.conf

@@ -65,6 +65,11 @@ CONFIG_MBEDTLS_MEMORY_DEBUG=y
 CONFIG_MBEDTLS_SHELL=y
 CONFIG_MBEDTLS_AES_ROM_TABLES=y
 
+# Credential shell, useful for debug
+CONFIG_TLS_CREDENTIALS_SHELL=y
+# Required for TLS crediential shell
+CONFIG_BASE64=y
+
 # More verbose Memfault component logs
 CONFIG_MEMFAULT_LOG_LEVEL_DBG=y