e2e/qa: name the gate for instant_allocation_price, not a version

[bgm-malbeclabs]

TestQA_MulticastSettlement's validate_instant_allocation_price_matches_chain skip path named a specific pinned version in two places:

// ansible/inventory/*/group_vars/all.yml, 0.5.10-1 at time of writing),
t.Skipf("... needs a release newer than the pinned 0.5.10-1 ...")

Testnet moved to 0.5.11-1 some time ago, so both read as "the pin is behind, bump it". It isn't. instant_allocation_price landed in doublezero-offchain#405 and is still under ## [Unreleased] there, so no published release carries it and no bump helps yet. That cost real time this week while debugging a query_onchain_seat_price failure on testnet.

Summary

• Name what actually gates the field, a doublezero-offchain release carrying doublezero-offchain#405, instead of a version number that rots.
• Keep the pointer to where the pin lives, with * corrected to <env>.
• Comment and skip message only. No behaviour change.

Testing Verification

• gofmt clean and go vet -tags=qa ./e2e/ passes.
• Not exercised against live QA hosts: this subtest only reaches the changed branch when the installed CLI does not report the field, which is the current state on testnet, and the branch it takes is unchanged.