doctor: improve error messages

[lucasbento]

Summary:

This is related to #694, it improves the error messages by maintaining consistency between the health checks with one separated function to log errors.

It also fixes a problem introduced on #743 where it shows undefined when the description is not provided on a health check.

Before

After

Test Plan:

1. Make a health check fail;
2. /path/to/cli doctor.

[thymikee]

One thing and we're good

[thymikee]

I think this is the one that causes extra space which is not necessary imho

[lucasbento]

Which space do you mean? the one before iOS or the one after iOS is done?

[thymikee]

[lucasbento]

That's because there's a space after each health check category (in this case Common and iOS) and also a space after each error is shown, that's why that extra space is there.

To be sincere I actually tried to get rid of it but there isn't an easy way to do at the moment, if we remove this last space then it can get to a funky UI when the previous health check succeeded but the next one failed.

[lucasbento]

The best way to do this is to actually check if the last health check failed, if so then print only one space instead of two.

[thymikee]

Let's figure this out later, this is a very minor inconvenience

[lucasbento]

Thanks for commenting about this though!