The session and event expanded metrics queries use implicit column
aliasing (`${column} name`) which causes a PostgreSQL syntax error
when the column name (like `os`) is followed by `name` without `AS`.
PostgreSQL parses `os name` ambiguously and fails with:
syntax error at or near "name"
The sibling file getPageviewExpandedMetrics.ts already uses the correct
`${column} as name` pattern. This applies the same fix to the session
and event queries.
Fixes#3970
