The ornamental design for fidget hand spinner, as shown and design.
FIG. 1 is a front perspective view of the fidget hand spinner showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a left elevational view thereof;
FIG. 4 is a right elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken lines shown in the figures are for the purpose of illustrating portions of the fidget hand spinner, which form no part of the claimed design.