[midgard] Add Empty Fields to Withdraw Events on Pool Suspend

Midgard drops events that do not contain the empty field, and since the withdraw events emitted during pool cycle do not have an originating transaction they were ignored. This is the cause of the current discrepancy on state for the ETH.HEGIC pool - @HooriRn is making corresponding Midgard corrections.

I'm not sure what makes most sense, but I also update the basis points on the withdraw event to 10000 since the position is close, but left the emitted RUNE and asset as 0 since nothing is sent back to LPs when the pool is suspended.