Jenkins Branch From Dynamic Repo using Active Choice parameter

Branch.groovy

team_name = TOREPLACE
username = TOREPLACE
password = TOREPLACE

urlStr= "https://bitbucket.org/!api/2.0/repositories/${team_name}/${Repository}/refs/branches?sort=-target.date&fields=pagelen,next,page,size,values.name&pagelen=100"

branches = []

def getBranches(url) {
    def baseUrl = new URL(url)
    HttpURLConnection connection = (HttpURLConnection) baseUrl.openConnection();
    connection.addRequestProperty("Accept", "application/json")
    String encoded = Base64.getEncoder().encodeToString(("${username}:${password}").getBytes(java.nio.charset.StandardCharsets.UTF_8));  //Java 8

    connection.setRequestProperty("Authorization", "Basic "+encoded);

    connection.with {
        doOutput = true
        requestMethod = 'GET'
        def jsResult = new groovy.json.JsonSlurper().parseText( content.text)
        
        jsResult.values.each { value -> 
            branches.add(value.name)
        }


        if(jsResult.next){
            getBranches(jsResult.next)
        }

    }
}



getBranches(urlStr)


return branches

Repository.groovy

team_name = TOREPLACE
username = TOREPLACE
password = TOREPLACE

urlStr = "https://bitbucket.org/!api/2.0/repositories/${team_name}?sort=-updated_on&fields=pagelen,next,page,size,values.name&pagelen=100"

repos = []

def getRepos(url) {
    def baseUrl = new URL(url)
    HttpURLConnection connection = (HttpURLConnection) baseUrl.openConnection();
    connection.addRequestProperty("Accept", "application/json")
    String encoded = Base64.getEncoder().encodeToString(("${username}:${password}").getBytes(java.nio.charset.StandardCharsets.UTF_8));  //Java 8

    connection.setRequestProperty("Authorization", "Basic "+encoded);

    connection.with {
        doOutput = true
        requestMethod = 'GET'
        def jsResult = new groovy.json.JsonSlurper().parseText( content.text)
        
        jsResult.values.each { value -> 
            repos.add(value.name)
        }


        if(jsResult.next){
            getRepos(jsResult.next)
        }
    }
}



getRepos(urlStr)

return repos

Actually the issue here is How to get credentials from Jenkins, there is a way to do so which is described in this link.
the code in this link is using some cloudbees plugin to fetch all the credentials. Which may cause a vulnerability by exposing the other credentials.