Sort personal projects on profile page by last_activity_at

What does this MR do and why?

The list of personal projects (for example on personal profile page) is now ordered by the project updated_at field. This MR will change that to last_activity_at, so it is consistent with project lists on group pages.

The specs are now expecting the returned project list to be sorted.

Changelog: changed

Related issue: #432410 (closed)

MR acceptance checklist

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Screenshots or screen recordings

Before	After

Database-related change

The order clause changed:

• master: ORDER BY project.updated_at DESC
• branch: ORDER BY project.last_activity_at DESC

Both fields have indexes.

Plan for master branch

 Sort  (cost=42.66..42.67 rows=1 width=824) (actual time=9.281..9.395 rows=1404 loops=1)
   Sort Key: projects.updated_at DESC
   Sort Method: quicksort  Memory: 1125kB
   Buffers: shared hit=1341
   I/O Timings: read=0.000 write=0.000
   ->  Nested Loop  (cost=1.00..42.65 rows=1 width=824) (actual time=0.074..6.395 rows=1404 loops=1)
         Buffers: shared hit=1338
         I/O Timings: read=0.000 write=0.000
         ->  Index Scan using index_namespaces_on_owner_id on public.namespaces  (cost=0.56..3.58 rows=1 width=4) (actual time=0.028..0.029 rows=1 loops=1)
               Index Cond: (namespaces.owner_id = 208581)
               Filter: ((namespaces.type)::text = 'User'::text)
               Rows Removed by Filter: 0
               Buffers: shared hit=5
               I/O Timings: read=0.000 write=0.000
         ->  Index Scan using index_projects_on_namespace_id_and_repository_size_limit on public.projects  (cost=0.44..39.04 rows=3 width=824) (actual time=0.043..5.434 rows=1404 loops=1)
               Index Cond: (projects.namespace_id = namespaces.id)
               Filter: (projects.visibility_level = 20)
               Rows Removed by Filter: 5
               Buffers: shared hit=1333
               I/O Timings: read=0.000 write=0.000

Plan for this branch

 Sort  (cost=42.66..42.67 rows=1 width=824) (actual time=2975.503..2975.777 rows=1404 loops=1)
   Sort Key: projects.last_activity_at DESC
   Sort Method: quicksort  Memory: 1125kB
   Buffers: shared hit=8 read=1333 dirtied=14
   I/O Timings: read=2914.132 write=0.000
   ->  Nested Loop  (cost=1.00..42.65 rows=1 width=824) (actual time=35.524..2955.256 rows=1404 loops=1)
         Buffers: shared hit=5 read=1333 dirtied=14
         I/O Timings: read=2914.132 write=0.000
         ->  Index Scan using index_namespaces_on_owner_id on public.namespaces  (cost=0.56..3.58 rows=1 width=4) (actual time=19.393..19.396 rows=1 loops=1)
               Index Cond: (namespaces.owner_id = 208581)
               Filter: ((namespaces.type)::text = 'User'::text)
               Rows Removed by Filter: 0
               Buffers: shared hit=2 read=3
               I/O Timings: read=19.076 write=0.000
         ->  Index Scan using index_projects_on_namespace_id_and_repository_size_limit on public.projects  (cost=0.44..39.04 rows=3 width=824) (actual time=16.105..2929.013 rows=1404 loops=1)
               Index Cond: (projects.namespace_id = namespaces.id)
               Filter: (projects.visibility_level = 20)
               Rows Removed by Filter: 5
               Buffers: shared hit=3 read=1330 dirtied=14
               I/O Timings: read=2895.056 write=0.000

How to set up and validate locally

GDK: Create three projects for user root, using this snippet in a Rails console:

Snippet

current_user = User.find(1)
activity_timestamps = [2.months.ago, 6.months.ago, 1.day.ago]
params = {namespace_id: current_user.namespace.id}

3.times do |i|
  last_activity_at = activity_timestamps[i]
  project_params = params.merge(name: "Last Activity at #{last_activity_at.to_date}")

  project = ::Projects::CreateService.new(current_user, project_params).execute

  project.update(last_activity_at: last_activity_at)
end

• Login on gdk using root account
• Goto http://localhost:3000/root
• On master: the personal project list should be ordered like the before image
• On this branch: ordered by last_activity_at

Related to #432410 (closed)