Both the "Set Radius" and "Set Weight" operators used
WM_operator_props_popup in the invoke callback. This seems to be
legacy code since almost no other operator does this (the exception is
PARTICLE_OT_rekey which should also maybe be changed).
All other operators using WM_operator_props_popup_* usually require
the user to enter a string or pick an element from an enum.

The patch removes the invoke callback of CURVE_OT_spline_weight_set
and CURVE_OT_radius_set. This also fixes T90063.

Additionally both these operators were only exposed in the context curve
menu. All other operators in the context menu are at least exposed once
more in one of the menus. The patch adds curve.spline_weight_set and
curve.radius_set to the "Curve" menu.