Allow read-only texts to be copied.

[krebil]

When some property types is in read-only mode you can't copy the text from them. I think it would be nice to allow this, so that it aligns with blocks (which are copyable in read-only mode)

For example: a translator only has edit rights to their own language but they can read the master language for reference. The default language's text will be grayed out and non-selectable.

If we could instead make the text grayed-out but selectable, then translators would still have access to the default language's texts for use in a tool on their local machine.