Change the Internal/External Setting. NOT READY

//// When using this script in the script console uncomment the next line:
def issueKey = 'ISSUE-1'
//// When using this script in a transition uncomment the next line:
// def issueKey = issue.key

String formName = "Form Name"

Closure getFormId = { def allProperties, String name ->
    for(def formProperty : allProperties){
        if(formProperty.key.equals("proforma.forms")){
            for(def p : formProperty.value.forms) {
                if(p.name.equals(name)){
                    return p.id
                }
            }
        }
    }
}

def proformaPropertyKeys = []
def allIssueProperties = get('/rest/api/3/issue/' + issueKey + '/properties/')
        .header('Content-Type', 'application/json')
        .asObject(Map)

if (allIssueProperties.status == 200){
    for(def property : allIssueProperties.body.keys){
      if(property.key.contains("proforma.forms")){
        proformaPropertyKeys.add(property.key)
      }
    }
}

def formProperties = []
if(!proformaPropertyKeys.isEmpty()){
    for(def key : proformaPropertyKeys){
        def property = get('/rest/api/3/issue/' + issueKey + '/properties/' + key)
                .header('Content-Type', 'application/json')
                .asObject(Map)
        if(property.status == 200){
            formProperties.add(property.body)
        }
    }
}

def formId

if(!formProperties.isEmpty()){
    formId = getFormId(formProperties, formName)
    boolean updateSecondForm = false
    for(def formProperty : formProperties){
        if(formProperty.key.equals("proforma.forms" + ".i" + formId) && formProperty.value.schemaVersion.equals(8)){
            if(formProperty.value.state.visibility == "i"){
                formProperty.value.state.visibility = "e"
            } else if(formProperty.value.state.visibility == "e"){
                formProperty.value.state.visibility = "i"
            }
            def insertProperty = put('/rest/api/3/issue/' + issueKey + '/properties/' + formProperty.key)
                              .header('Content-Type', 'application/json')
                              .body(formProperty.value)
                              .asString()
            updateSecondForm = true
        }
    }
    if(updateSecondForm){
        for(def formProperty : formProperties){
            if(formProperty.key.equals("proforma.forms")){
                for(def form : formProperty.value.forms){
                    if(form.id.equals(formId)){
                        if(form.internal == true){
                            form.internal = false
                        } else if(form.internal == false){
                            form.internal = true    
                        }
                        def insertProperty = put('/rest/api/3/issue/' + issueKey + '/properties/' + formProperty.key)
                                          .header('Content-Type', 'application/json')
                                          .body(formProperty.value)
                                          .asString()
                    }
                }
            }
        }
    }
}