not every ingress controller is nginx

[msporleder]

https://github.com/apache/solr-operator/blob/630efa053f88333587ca6eeca94887aa2a65f61b/controllers/util/solr_util.go#L1088-L1104

Although this is pretty harmless as noise I'm not sure why this assumption was hard-coded in.

Can you consider adding if customOptions.IngressClassName == "nginx" or similar?