ref: Log warning when debug source excedes item size limit

[kamilogorek]

This will produce the warning below:

WARN    2022-08-04 12:32:50.920489 +02:00 Source exceded maximum item size limit (116303). /Applications/Xcode.app/usr/include/c++/v1/chrono
WARN    2022-08-04 12:32:50.961811 +02:00 Source exceded maximum item size limit (103509). /Applications/Xcode.app/usr/include/c++/v1/atomic
WARN    2022-08-04 12:32:50.980145 +02:00 Source exceded maximum item size limit (157727). /Applications/Xcode.app/usr/include/c++/v1/type_traits
WARN    2022-08-04 12:32:51.003650 +02:00 Source exceded maximum item size limit (169525). /Applications/Xcode.app/usr/include/c++/v1/string
WARN    2022-08-04 12:32:51.056923 +02:00 Source exceded maximum item size limit (112450). /Applications/Xcode.app/usr/include/c++/v1/vector

Question is, whether we should leave it as WARN, which is on by default, or make it DEBUG, which is opt-in.
I'm not sure how common this case is, and don't want the logs to get cluttered too much.

cc @bruno-garcia

resolves #1304
ref getsentry/sentry-unity#920 (comment)

[Swatinem]

I’m okay with making this a warning, as it prompts people to fix their config, or makes it very obvious why they don’t get source context for that file