resize_in_steps should be ignored when window is maximized

[thejavascriptman]

Describe the bug
If resize_in_steps is enabled and window is maximized, when zooming-in or out the kitty window gets resized.

To Reproduce
Steps to reproduce the behavior:

1. Add resize_in_steps yes to the kitty.conf file and save
2. Relaunch kitty
3. Maximize kitty
4. Zoom in or out by using ctrl+shift+equal or ctrl+shift-minus
5. The kitty window will resize

Expected behavior
The kitty window does not resize when maximized.

Environment details
OS: Arch Linux with kernel 5.11 running under Plasma on 5.21.4 X11

kitty 0.19.3 created by Kovid Goyal
Linux arch 5.11.13-arch1-1 #1 SMP PREEMPT Sat, 10 Apr 2021 20:47:14 +0000 x86_64
Arch Linux \r (\l)
Loaded config files: /home/user/.config/kitty/kitty.conf
Running under: X11

Config options different from defaults:
initial_window_height (54, 'cells')
initial_window_width  (220, 'cells')
resize_in_steps       True
window_border_width   (1.0, 'px')
window_padding_width  FloatEdges(left=1.0, top=0, right=1.0, bottom=0)

Additional context
Not happening with kitty --config NONE most likely because resize_in_steps is not enabled by default