stack-buffer-overflow in simple str to doublestr

stack-buffer-overflow in simple str to doublestr: a task in MiMo-V2.6-RL-harbor-cyber: MiMo-V2.6-RL Cyber (Harbor) (Harbor dataset). AddressSanitizer: stack-buffer-overflow in function simple str to doublestr in file libical/src/libical/icalvalue.c