Fix TextEdit selection bounds for multiple lines

If we select from the beginning of a line to the previous line the
selection painting process was including the first character of the
line where we started, but it shouldn't be included (as the cursor
started in pos=0).

src/ui/textedit.cpp

@@ -860,7 +860,7 @@ gfx::Rect TextEdit::Line::getBounds(const int glyph) const
 gfx::Rect TextEdit::Line::getBounds(int startGlyph, int endGlyph) const
 {
   if (startGlyph == endGlyph)
-    return getBounds(startGlyph);
+    return {};
 
   ASSERT(endGlyph > startGlyph);