Fix outside contributor workflow to use value from user input

[sarah-tuva]

Describe your changes

• Updated the step "actions/checkout@v2" for each job in the outside contributor workflow to use the prNumber input to check out the PR branch. This should avoid the need to enter the PR and have to select the correct branch when running the workflow.
• Renamed the job "dbt_v1.6.3_snowflake_build_full_clinical.yml" to "dbt_v1.6.3_snowflake_build_full_refresh.yml" to match the pattern of the other jobs. This job runs both claims and clinical, not just clinical.

How has this been tested?

Used GitHub Act to test the workflow locally and confirmed the PR input was being used to check out the PR branch rather than checking out main by default.

Reviewer focus

Please summarize the specific items you’d like the reviewer(s) to look into.

Checklist before requesting a review

• I have added at least one Github label to this PR (bug, enhancement, breaking change,...)
• My code follows style guidelines
• (New models) YAML files are categorized by sub folder and models listed in alphabetical order
• (New models) I have added a config to each new model to enable it for claims and/or clinical data
• (New models) I have added the variable tuva_last_run to the final output
• (Optional) I have recorded a Loom to explain this PR

Package release checklist

• I have updated dbt docs
• I have updated the version number in the dbt_project.yml

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