ci: simplify filter for running JS tests (#5024)
Using ! syntax creates a union set between the filters and
catches many more tests than we want to run in this case. Using
`./packages` works better, because even though it includes packages that
the turborepo team does not own, the filter by changed workspaces should
exclude them. Even if it doesn't, it's ok to run all JS package tests
without accounting for code ownership.
