MLFlow runName passed as metadata not being set as Candidate Name

What does this MR do and why?

MLflow Client passed the name for a run a the metadata with key mlflow.runName, which is not taken into account as the name for the candidate

How to set up and validate locally

1. Enable the Feature flag

   echo "Feature.enable(:ml_experiment_tracking)" | bundle exec rails c

2. Create a Project and an personal access token:

   export PROJECT_ID=<Your Project Id>
   export GITLAB_PAT=<your api token>

3. Create an Experiment:

   curl -X POST -H "Authorization: Bearer $GITLAB_PAT" \
       -H "Content-Type: application/json"  \
       -d '{"name":"some_experiment","tags":[{"key":"a", "value":"b"}]}' \
       http://gdk.test:3000/api/v4/projects/$PROJECT_ID/ml/mlflow/api/2.0/mlflow/experiments/create

4. Create a Run, notice Candidate name is now "a_run"

   curl -X POST -H "Authorization: Bearer $GITLAB_PAT" -H "Content-Type: application/json" --data '{"experiment_id":1,"tags":[{"key":"mlflow.runName", "value":"a_run"}]}' http://gdk.test:3000/api/v4/projects/$PROJECT_ID/ml/mlflow/api/2.0/mlflow/runs/create

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #388116 (closed)