added mlx90393 mag support

[maxxmudd]

Adafruit_SensorLab.cpp -added a detectMLX90393 method -modified the getMagnetometer method to include detectMLX90393 condition

Adafruit_SensorLab.h -set the file to include the Adafruit_MLX90393 header file -added a detectMLX90393 boolean -added pointer to Adafruit_MLX90393 class, set to NULL

Comments: -these changes have been tested using the mag_hardiron_simplecal.ino example

[ladyada]

hihi we can review once it passes CI see errors by clicking DETAILS on the CI failures

for example, please add the new dependancy here https://github.com/adafruit/Adafruit_SensorLab/blob/master/library.properties

[ladyada]

ok! next run clang-format and/or write any missing doxygen https://learn.adafruit.com/contribute-to-arduino-with-git-and-github

[maxxmudd]

I will be doing a bit more digging on this before submitting again. Thank you for being patient and giving me feedback.

[ladyada]

you can do it!! 👍