The ornamental design for a needleholderassembly, as shown and described.
FIG. 1 is a perspective view of the needle holder assembly; FIG. 2 is a
side elevational view of the needle holder assembly of FIG. 1; FIG. 3 is a
side elevational view of the needle holder needle assembly of FIG. 1,
rotated 90°; FIG. 4 is a is a side elevational view of the needle
holder needle assembly of FIG. 1, rotated 270°; and, FIG. 5 is a
top plan view of the needle holder assembly of FIG. 1.