ID scheme for child simulation is weird

[gzeoneth]

Child simulation (e.g. the L1 execution of a L2 proposal, the retryable execution of a L1 transaction) currently use a naive id scheme here:

governance-seatbelt/index.ts

Line 57 in 401c99f

offset += 1000000 // reserve spaces for retryable exections

governance-seatbelt/index.ts

Line 119 in 401c99f

offset += 10000

which is weird and because arb governor do not use sequential numbering it make the id like the following:

L2 Proposal Execution:

Running for proposal ID 0xbb95ace4f588148ad3a1d9bc233dbef1002971173556b5826a829962c3edd81c...

L1 Timelock Execution:

Running for proposal ID 0xbb95ace4f588148ad3a1d9bc233dbef1002971173556b5826a829962c3edd81d...

Retryable Execution:

Running for proposal ID 0xbb95ace4f588148ad3a1d9bc233dbef1002971173556b5826a829962c3edff2d...