As part of #20925 and #21341 we added an "all-fields" mode to the
`query_string` and `simple_query_string`. This would expand the query to
all fields and automatically set `lenient` to true.
However, we should still allow a user to override the `lenient` flag to
whichever value they desire, should they add it in the request. This
commit does that.
11da09e9bc