Bug fix on inverted leveling Y axis

[digant73]

BUG FIXES:

• Wrong inverted leveling Y axis: bug introduced by Corner leveling bugfix #2655 claimed as bug fix for a not existing bug introduced by PR Some improvements + bug fixes #2233. The usual propaganda always based on "no bug report from real users" motivated by the life style::

  • you did something? I will change it without any reason and even without a perfect knowledge of the code! From now on I will start an infinite rework on that code!
  • you re-fixed something I completely messed up for no reason at all (e.g. Mesh Editor - Overhaul #2737)? I will even continue to apply my personal changes (not fixing something wrong in your code such as in current Bugfixes, restoration, cleanup, speedup, some FW size reduction #2776, Another FW size reduction #2778) on top of your real fixes (that I will never even find by myself as all the attempts made in [BUG] TFT35 Mesh Edit throws M14 and unable to adjust Mesh #2786) even if you wasted your free time twice (5 days for original code + 5 for fixes requiring only 3 consecutive PRs)!
  • you have a look at the possible bugs reported by users and possibly try to find/fix a possible real bug? I will try to hijack the communication on my Discord channel (e.g. [Q] Random pauses or hesitation when printing. #2761) although BTT also provides the "Discussion" tab already available for "sharing" extra details!
  • you provide something here when really necessary/needed? I have nothing better to do in my free time so I will also invent PRs for no bugs ever reported, a fix/rework of something perfectly working, a replacement of perfectly working standard C functions with my perfectly broken new ones etc...! Who cares about bugs! they will be re-fixed by others sooner or later!

  Bug report Inverted Axes ini option problem[FR] (feature request title) #2742 reporting the broken logic was needed to re-fix something that was perfectly working. Just as an history recap, LY parameter properly introduced by BTT based on real FR requests. Unfortunately, even the presence of the comment "leveling Y axis" added in both LevelingControl.c and config.c source code was not enough to avoid the introduction of the bug.

fixes #2742

PR STATE: ready for merge