debug: secondary client build should not reuse solve opt ref

Signed-off-by: Justin Chadwell <me@jedevc.com>

build/result.go

@@ -72,6 +72,8 @@ func getResultAt(ctx context.Context, c *client.Client, solveOpt client.SolveOpt
 	resultCtxCh := make(chan *ResultContext)
 	errCh := make(chan error)
 	go func() {
+		solveOpt := solveOpt
+		solveOpt.Ref = ""
 		_, err := c.Build(context.Background(), solveOpt, "buildx", func(ctx context.Context, c gateway.Client) (*gateway.Result, error) {
 			ctx, cancel := context.WithCancel(ctx)
 			defer cancel()