fix: Return number of runs in a given project for GetProjects

[AmanuelAaron]

Ticket

ET-313

Description

Return the run count in for a given project everywhere we get num experiments.

Test Plan

Make sure that the Flat Runs feature flag is on. Go to any workspace page and check the response body of the projects call. Verify that numRuns is correct by selecting each project in the workspace.

Checklist

• Changes have been manually QA'd
• New features have been approved by the corresponding PM
• User-facing API changes have the "User-facing API Change" label
• Release notes have been added as a separate file under docs/release-notes/
  See Release Note for details.
• Licenses have been included for new code which was copied and/or modified from any external code

[netlify]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	b3e9058
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/667c1a9d06379000080c8b85

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 49.80%. Comparing base (651264b) to head (b3e9058).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9557   +/-   ##
=======================================
  Coverage   49.80%   49.80%           
=======================================
  Files        1247     1247           
  Lines      162243   162249    +6     
  Branches     2888     2888           
=======================================
+ Hits        80805    80813    +8     
+ Misses      81266    81264    -2     
  Partials      172      172           

Flag	Coverage Δ
backend	43.89% <80.00%> (+<0.01%)	⬆️
harness	63.75% <100.00%> (+<0.01%)	⬆️
web	46.16% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
harness/determined/common/api/bindings.py	40.22% <100.00%> (+<0.01%)	⬆️
master/internal/project/postgres_project.go	57.62% <100.00%> (+0.63%)	⬆️
master/pkg/model/project.go	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes