The ornamental design for a flexiblebottle, as shown and described.
FIG. 1 is a perspective view of my new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken line showing of a mouthpiece in FIGS. 1-7 and an opening shown in FIGS. 1-4 is included for the purpose of illustrating environmental structure and forms no part of the claimed design.