KateMainWindow: Prevent hamburger button from being pushed into the overflow
Qt lays out toolbars left to right, so we can end up in a situation where the main toolbar overflows and the hamburgerBar with the single hamburger menu button also gets an overflow.
This makes the menu button hard to access and two carets next to each other looking terrible.
Before
After
Resized my window smaller, could always access the hamburger menu.
Tried with Kate and KWrite on Breeze, Oxygen, Fusion, Windows 95 style at both 1x and 2x scale.