WA-NEW-011: ES7 compatibility pass for remaining query builders

[jhill]

Goal: Ensure all query builders referencing query_string options removed/changed in ES7 are compatible (beyond admin index search already fixed in WA-NEW-005).

Scope: Includes core/app/queries/workarea/search/product_search.rb and core/app/queries/workarea/search/help_search.rb.

Verify:

• bundle exec ruby -Icore/test core/test/queries/workarea/search/product_search_test.rb
• bundle exec ruby -Icore/test core/test/queries/workarea/search/help_search_test.rb
  Branch pattern: wa-new-011-*
  PR target: next

[kitcommerce]

Implemented on branch wa-new-011-es7-query-string (commit 718743f): removed deprecated use_dis_max option from query_string queries in ProductSearch/HelpSearch for ES7 compatibility.

Verify: bundle exec ruby -Icore/test core/test/queries/workarea/search/product_search_test.rb (now passes; previously raised 400 parsing_exception for use_dis_max).

[kitcommerce]

Heads up: this issue is still OPEN but has label status:done. If the work is truly complete/merged, we should close the issue (or swap the label back to status:ready/in-progress). Let me know if you'd like me to propose the exact cleanup (close vs relabel) once we confirm the related commit/PR.

[kitcommerce]

Label corrected to status:in-progress (PR already open: #634).