The ornamental design for a foldable petcageframe, as shown and described.
FIG. 1 is a top perspective view of the foldable pet cage frame of our new design;
FIG. 2 is a bottom 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 elevational view thereof;
FIG. 6 is a right-side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines shown in the drawings are for the purpose of illustrating portions of the foldable pet cage frame that form no part of the claimed design.