Aggregate filters do not get pushed down to table scan

[andygrove]

Describe the bug
Aggregate filters do not get pushed down to table scan. This results in invalid query plans. In this example, the column user_id has not been pushed down to the table scan.

Projection: #SUM(user_table_1.b) FILTER (WHERE #user_id = Int64(2)) AS S1, #SUM(user_table_1.b) AS S2
  Aggregate: groupBy=[[]], aggr=[[SUM(#user_table_1.b) FILTER (WHERE #user_id = Int64(2)), SUM(#user_table_1.b)]]
    TableScan: user_table_1 projection=[b]

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Expected behavior
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Additional context
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