Overlap partial_matching? function

What does this MR do and why?

Hi, Gitlab

We found one issue related with fuzzy search issue.

When user search 2 Chinese chars and sort with priority, gitlab will NOT enable fuzzy search, however search 2 Chinese chars and sort created, gitlab will enable fuzzy search.

In JiHu, even fuzzy search a one Chinese character is meaningful to user, no matter which field is sorted, so we need enable fuzzy search always.

after reading the code, we found the key method partial_matching? of fuzzy search, which will compare query.length with min_chars_for_partial_matching, which disable fuzzy search when query.length less than 3.

following is the partial_matching? method code

        # gitlab/lib/gitlab/sql/pattern.rb
        def partial_matching?(query, use_minimum_char_limit: true)
          return true unless use_minimum_char_limit

          query.length >= min_chars_for_partial_matching
        end

Even there is param use_minimum_char_limit in partial_matching? method to control the method result, but we still cannot use it, because this param value depend on method use_cte_for_search? when we search issue and sort with priority, which disable fuzzy search.

following is the issue search code

# app/finders/issuable_finder.rb
def by_search(items)
    ...
    # if use_cte_for_search? is false, it will require minimum chat limit to enable fuzzy_search
    items.full_search(search, matched_columns: params[:in], use_minimum_char_limit: !use_cte_for_search?)
  end

  def use_cte_for_search?
    strong_memoize(:use_cte_for_search) do
      next false unless search
      # when sort with priority during search, this method will return false
      next false unless default_or_simple_sort? 

      attempt_group_search_optimizations? || attempt_project_search_optimizations?
    end
  end

so we need prepend method partial_matching?, and since method partial_matching? belongs to class method in ActiveConcern, so not only we need prepend Gitlab::SQL::Pattern, but also need prepend Gitlab::SQL::Pattern::ClassMethods, you can find similar example in IssueableLink

Screenshots or screen recordings

this link search “审计” with priority sort, https://gitlab.com/wd665544/issue-test/-/issues/?search=%E5%AE%A1%E8%AE%A1&sort=priority_desc&state=opened&first_page_size=20 should show 3 issues, but only show 1

this link search “审计” with created_at sort, https://gitlab.com/wd665544/issue-test/-/issues/?search=%E5%AE%A1%E8%AE%A1&sort=created_date&state=opened&first_page_size=20

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