caches will only inherit basic-spec if they have custom properties

[TheGeb]

I would like to define a cache in code with
@Cacheable(cacheNames = "example_cache"
and have it inherit the basic-spec without any changes to property files

However, currently CaffeineSpecResolver.getCaffeineSpec will only apply the basic-spec to caches which have a non-blank value for coffee-boots.cache.spec.example_cache