The ornamental design for a toothpastetube with fingerbrush, as shown and described.
FIG. 1 is a top and left side perspective view of the toothpaste tube with finger brush showing my new design;
FIG. 2 is a left side view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is rear view thereof; and,
FIG. 5 is a front view thereof.
The broken line showing of portion of the claimed design is included for the purpose of illustrating environmental structure and forms no part of the claimed design.