From my general experience with secondary offerings, I'd say it depends how large it is. Market doesn't blink at small secondary offerings and they tend to have very little effect. A large offering would be considered dilutive and cause a drop.
If it's low-interest long-term corporate bonds it would probably be viewed as a positive, indicating that Tesla has better access to financing.
High-interest corporate bonds would be viewed as a negative, indicating that Tesla has worse access to financing.