With the introduction of single types in 6.x, the `_type` field is no longer
indexed, which leads to certain queries that were working before throw errors
now. One such query is the `range` query, that, if performed on a single typer
index, currently throws an IAE since the field is not indexed.
This change adds special treatment for this case in the TypeFieldMapper,
comparing the range queries lower and upper bound to the one existing type and
either returns a MatchAllDocs or a MatchNoDocs query.

Relates to elastic#31632
Closes elastic#31476