Make table entries selectable

[bkonyi]

It's currently not possible to select text from entries in a table, making it difficult to copy-paste things like file paths from stack traces.

cc @liamappelbe

[kenzieschmoll]

We can make the table entries use SelectableText, though there are some usability issues that arise from this: flutter/flutter#129590.

Out of the box, this does change the select behavior of the table rows as well. For example in a tree table, clicking on a row should expand or collapse the row, but when we use SelectableText, the select gesture takes precedence over the on tap handler.

[kenzieschmoll]

This issue may also be blocked by flutter/flutter#80435. SelectableText overflow property is not working.

[LongCatIsLooong]

SelectableRegion in theory allows you to select static text.