Fix benchmark failures when using `insecure_zero_ed` flag (#5354)

Currently, when the pallet is compiled with the `insecure_zero_ed flag`,
benchmarks fail because the minimum balance is set to zero.

The PR aims to resolve this issue by implementing a placeholder value
for the minimum balance when the `insecure_zero_ed` flag is active. it
ensures that benchmarks run successfully regardless of whether this flag
is used or not