Allow query/query_range keys to contain numbers

What does this MR do?

A number is a valid Prometheus query. Such queries are usually used to display a threshold on a chart. We used to previously allow numbers in the query/query_range key. In !34508 (merged) we started removing newlines from the query/query_range key in order to allow for multiline queries. This, unfortunately, had the side effect of throwing an error when the query/query_range key contained a number.

Issue: #236014 (closed)

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Does this MR meet the acceptance criteria?

Conformity

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