Re-enable text selection in the "Search inside" panel

Previous versions of bookreader allowed the user to select-and-copy text within the "Search inside" panel. This is now no longer possible, as now the search results have now been turned into buttons.

Having the ability to select text from the "Search inside" panel is important because it allows users to quickly select-and-copy text snippets they may, for example, be quoting from a book. While *some* books do allow selecting text with the mouse from the page of the book, there are many that do not. Here is an example:
https://archive.org/details/sim_flag-of-our-union_1856-02-23_11_8/page/n2/mode/1up?q=%22On+this+particular+morning%22

Using this example, as it is now impossible to select-and-copy the text in the snippet of the search result, the user's only option is to download the Full Text of the book and Ctrl+F for what they were looking for. Or, to manually retype what is seen on the screen. Both options are needlessly more difficult compared to how it was before.

**Proposed solution**
Re-enable text selection from the "Search inside", making it how it was in the previous version before the search results were made into buttons.