shell: make the backend thread name variable generic

Rename the shell backend `thread_name` variable to just `name`,
to be used for other things not specific to thread later.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>

include/zephyr/shell/shell.h

@@ -863,7 +863,7 @@ struct shell {
 
 	LOG_INSTANCE_PTR_DECLARE(log);
 
-	const char *thread_name;
+	const char *name;
 	struct k_thread *thread;
 	k_thread_stack_t *stack;
 };
@@ -910,7 +910,7 @@ extern void z_shell_print_stream(const void *user_ctx, const char *data,
 		.stats = Z_SHELL_STATS_PTR(_name),			      \
 		.log_backend = Z_SHELL_LOG_BACKEND_PTR(_name),		      \
 		LOG_INSTANCE_PTR_INIT(log, shell, _name)		      \
-		.thread_name = STRINGIFY(_name),			      \
+		.name = STRINGIFY(_name),				      \
 		.thread = &_name##_thread,				      \
 		.stack = _name##_stack					      \
 	}

subsys/shell/shell.c

@@ -1392,7 +1392,7 @@ int shell_init(const struct shell *sh, const void *transport_config,
 				  SHELL_THREAD_PRIORITY, 0, K_NO_WAIT);
 
 	sh->ctx->tid = tid;
-	k_thread_name_set(tid, sh->thread_name);
+	k_thread_name_set(tid, sh->name);
 
 	return 0;
 }