[nrf fromlist] net: lib: tls_credentials_shell: Add a config for heap

The volatile backend stores the credentials on the heap, so, explicitly
add a config option that can be overridden in case there are more certs
than the default.

Upstream PR #: 87656

Signed-off-by: Chaitanya Tata <[email protected]>
(cherry picked from commit 057c3ed)

Author: krish2718

subsys/net/lib/tls_credentials/Kconfig.shell

@@ -32,4 +32,14 @@ config TLS_CREDENTIALS_SHELL_DIGEST_BUF_SIZE
 
 	   Also used to print error messages if digest generation fails.
 
+if TLS_CREDENTIALS_BACKEND_VOLATILE
+
+config HEAP_MEM_POOL_ADD_SIZE_TLS_CRED_SHELL
+	int "TLS credentials shell memory pool size"
+	# default 4 certs and each assume 1500 bytes
+	default 6000
+	help
+	  The size of the memory pool used by the TLS credentials shell.
+endif # TLS_CREDENTIALS_BACKEND_VOLATILE
+
 endif # TLS_CREDENTIALS_SHELL