[dy] Optimize pipeline schedule queries

[dy46]

Description

Optimize some schedule queries. Some queries were pulling all pipeline runs for a schedule when they just needed to get a count which could be very inefficient when there are a lot of runs.

How Has This Been Tested?

• Tested locally
• Unit tests

Checklist

• The PR is tagged with proper labels (bug, enhancement, feature, documentation)
• I have performed a self-review of my own code
• I have added unit tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• If new documentation has been added, relative paths have been added to the appropriate section of docs/mint.json

cc: @wangxiaoyou1993

[wangxiaoyou1993]

Looks good after rebase master branch