fix filter node drilldown for number columns

[marthasharkey]

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[kazcw]

IMO mutable non-reactive data in a reactive API is a code smell. It avoids some unneeded reactivity overhead (usually for an event handler)--but it's only a half-measure: It requires the caller to eagerly keep the data up-to-date.

Rather than push data to event handlers, give them a way to pull it as needed--something like:
getColumnValueToEnso: (columnName) => ((columnValue: string) => Ast.Owned<Ast.Expression>)

Then in TableVisualization, the colTypeMap (that will be used internally by the getColumnValueToEnso implementation) can be a computed so that it is only constructed when an event handler needs the data.

[kazcw]

{} is a bit hazardous as the basis for a map, because it isn't empty--it has properties like toString. This can be avoided by using a Map. (Alternatives would include constructing it with Object.create(null) or querying it with Object.hasOwn, but Map expresses intent better).