Removing line breaks in text copied from a flex container

You're going to have to find another solution.

In a flex container the child elements ("flex items") are automatically "blockified" (details).

This means that a flex item takes on some of the characteristics of block-level elements, including taking up all space in the row.

You may be tempted to just set the items to display: inline. This would be a waste of time. The display value of flex items is controlled by the flex algorithm, and any attempt to override that setting is ignored.