This was added in 9609af3c23 as part of a LSC.
The RequiresNonNull annotation doesn't work anymore (it doesn't
recognize the outer class member and instead tries to find
the same variable on the inner class). So instead of suppressing
the warning of the non-fulfilled precondition, we can just
check the non-nullness directly and remove the precondition.
PiperOrigin-RevId: 367593941
1dd96cd8fb