Remove un-used methods in Vulnerability::Finding

Vulnerability::Finding.for_pipelines_with_sha is a cross joining to a CI table. However it is not used - removed in 44a31d8b.

Vulnerability::Finding.batch_count_by_project_and_severity is also joining to a CI table. It is also unused since 3e1bc4f3

Proposal

• Remove Vulnerability::Finding.for_pipelines_with_sha

• Remove Vulnerability::Finding.batch_count_by_project_and_severity