ARI: Fixed unload mode for unload module.

Changed the unload mode to AST_FORCE_SOFT from AST_FORCE_FIRM,
which would unload a module even if it was in use.

* Changed unload mode to proper mode

ASTERISK-25173

Change-Id: If2402487b5bce05d9770f25f65f5c8e292ad5533

res/ari/resource_asterisk.c

@@ -300,7 +300,7 @@ void ast_ari_asterisk_unload_module(struct ast_variable *headers,
 	struct ast_ari_response *response)
 {
 	int unload_result;
-	enum ast_module_unload_mode unload_mode = AST_FORCE_FIRM;
+	enum ast_module_unload_mode unload_mode = AST_FORCE_SOFT;
 
 	ast_assert(response != NULL);