CI: Fetch compat ruleset from S3_2
Once main no longer does ruleset conversion from 3.1 format ( #47397 ), CI needs to fetch rulesets for conversion test from S3_2.
Patch attached. Exact S3_2 commit hash must be updated just before pushing this in.
Once main no longer does ruleset conversion from 3.1 format ( #47397 ), CI needs to fetch rulesets for conversion test from S3_2.