backport: Add user's contributions to search

[AyakorK]

🎩 Description

We had to backport a fix related to the issue that occured when you searched a user's name, and that you only saw the user's profile and not his contributions.

That's a backport from PR #971 that was based on 0.31 and now backported to 0.29

Testing

If you already have an application booted or in production you have to run this command to reindex every searchable fields

bundle exec rails runner "
%w[
  Decidim::Proposals::Proposal
  Decidim::Meetings::Meeting
  Decidim::Debates::Debate
  Decidim::Blogs::Post
].each do |klass_name|
  begin
    klass_name.constantize.find_each(&:try_update_index_for_search_resource)
    puts \"✅ #{klass_name} reindexed\"
  rescue => e
    puts \"⚠️ #{klass_name} skipped : #{e.message}\"
  end
end
"

• Navigate through participatory processes and proposals
• Get the name of an author
• Search author's name in the search bar
• Make sure the author's contributions are appearing correctly

📌 Related Issues

Link your PR to an issue

• Fixes https://github.com/orgs/OpenSourcePolitics/projects/26/views/1?pane=issue&itemId=153913832&issue=OpenSourcePolitics%7Cintern-tasks%7C349

Tasks

• Add specs
• Make a global extend on multiple searchable components

[Stef-Rousset]

LGTM !

[BarbaraOliveira13]

LGMT