Let EnsoMultiValue.to_text delegate to first type to_text

[JaroslavTulach]

Based on to_text discussion, but overall question is: what should EnsoMultiValue do with Any methods? If we delegate to_text to the first type, then we should probably delegate all of them. @radeusgd originally wrote:

IMO to_text of first type is best. It does hide the 'other values' and that is not ideal, but given the kind of use cases we want to use multi-values for (e.g. the Column & Integer_Column), I think that delegating to the first type is the best we can do to keep this sensible.

In that regard, perhaps to_text shouldn't be any different than e.g. to_js_object or to_defautl_visualization_data that we use to visualize the values. These will also delegate to the first value.

Originally posted by @radeusgd in #11600 (comment)

[JaroslavTulach]

As a side note: Any.to should probably use EnsoMultiValue as self: #11897 (comment)