Backport: Docs: Fix RPC doc generation script after !16869

Backport of !16961 (merged)

What

Fix the script generating the documentation of the RPCs

Why

Cause it is very useful to have it working.

How

Since !16869 (merged) raised the retention period for the DAL, it requires the L1 node to keep more history. On sandboxed network where cycle length is 8 blocks, it requires to change history mode of the L1 node. In particular, this script launches a L1 node on sandbox, hence it requires this raising in history-mode parameter.

Manually testing the MR

make -C docs openapi should now work.