Redmine

This patch updates `Issue#relations` method to efficiently fetch both `relations_from` and `relations_to` using a single ActiveRecord query. This optimization reduces database calls and improves performance.

Before:

  IssueRelation Load (0.2ms)  SELECT "issue_relations".* FROM "issue_relations" WHERE "issue_relations"."issue_from_id" = $1  [["issue_from_id", 1]]
  ↳ app/models/issue.rb:1169:in `relations'
  IssueRelation Load (0.5ms)  SELECT "issue_relations".* FROM "issue_relations" WHERE "issue_relations"."issue_to_id" = $1  [["issue_to_id", 1]]
  ↳ app/models/issue.rb:1169:in `relations'

After:

  IssueRelation Load (0.7ms)  SELECT "issue_relations".* FROM "issue_relations" WHERE (issue_to_id = 1 OR issue_from_id = 1)
  ↳ app/models/issue.rb:1171:in `sort'