The ornamental design for a stowablepetleash and collar, as shown and described.
FIG. 1 is a perspective view of a stowable pet leash and collar combination showing my new design in a partially rolled condition;
FIG. 2 is a second perspective view in a partially rolled condition; and,
FIG. 3 is a perspective view in a fully extended condition.
The carabineer clip depicted by broken lines in the drawings has been shown to illustrate a portion of the stowable pet leash and collar that forms no part of the claimed design.