When setting an environment variable equal to a blank string it comes back a the literal string of `null` instead of being a blank string

Steps to reproduce:

1. Create a new pipeline job with the following definition:

   pipeline {
       agent any
       environment {
           VERSION_SUFFIX = ''
       }
       stages {
           stage("test") {
               steps{
                   echo "env.VERSION_SUFFIX = ${env.VERSION_SUFFIX}"
               }
           }
       }
   }
   

1. Run said pipeline
2. Observe the output is `
   env.VERSION_SUFFIX = null

Expected result:

Normally I would expect it to just be a blank string or nothing there