Improve log output during SDK init

[markushi]

Description

io.sentry.android.core.LoadClass.loadClass spits out an exception to the log output if a certain class is not available (androidx libs, Jetpack Compose) - this can be quite confusing for anyone using our SDK.

Fixes getsentry/sentry-dart#2824 (comment)

[feinstein]

There are so many logs, including some about serialisation and installed modules. Honestly this all seems like debug info that's helpful to you, but should be silent for the end user.

I would recommend that you put all those logs behind a flag, so they can enabled when you are developing the sdks.

[markushi]

@feinstein just to clarify: You seem to have SDK logging enabled at the debug level for your builds, so it's expected to be quite verbose. See https://docs.sentry.io/platforms/dart/guides/flutter/configuration/options/#debug for more details.

[feinstein]

Ok, but I think there's a difference between the debugs logs that are useful for devs and the logs that are useful to the SDK development. I feel that the logs are just too verbose to the point where they are useful for SDK development, not the users. And this being true by default when we run in debug (which is what everyone does during development) will just flood everyone's terminal during development.