fix: add explicit AS keyword for PostgreSQL column alias in session and event queries

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

src/queries/sql/events/getEventExpandedMetrics.ts

@@ -58,7 +58,7 @@ async function relationalQuery(
       sum(${getTimestampDiffSQL('t.min_time', 't.max_time')}) as "totaltime"
     from (
       select
-        ${column} name,
+        ${column} as name,
         website_event.session_id,
         website_event.visit_id,
         count(*) as "c",

src/queries/sql/sessions/getSessionExpandedMetrics.ts

@@ -65,7 +65,7 @@ async function relationalQuery(
       sum(${getTimestampDiffSQL('t.min_time', 't.max_time')}) as "totaltime"
     from (
       select
-        ${column} name,
+        ${column} as name,
         ${includeCountry ? 'country,' : ''}
         website_event.session_id,
         website_event.visit_id,