:bug: Fix regression in indent-guide in React editor

Previously the indent guide was always showing on the whitespace only lines in the React editor. This is the same behavior as in the old editor and had the same fix, just ported to `LinesComponent`.

Still TODO:
- [x] Figure out how to port over the test from @kevinsawicki's change

See: 314833bbac33bdb7c45594550d8d10559dd2de9c
Fixes #2274