[BUG] [Java Service]Nothing is shown as displayName for "sl-Latn-IT-ROZAJ" locales in its language.

Describe the bug
commit: c7afc3bee93563af3c7073adfdd5cbd9b584ca0e
Nothing is shown as displayName for "sl-Latn-IT-ROZAJ" locales in its language.

To Reproduce
Steps to reproduce the behavior:

1. Put a json file with name: messages_sl-Latn-IT-ROZAJ.json in VMwareVIPLocale&1.0.0 bundles.
2. Request its displayname with "http://serviceip:8091/i18n/api/v2/locale/supportedLanguageList?productName=VMwareVIPLocale&version=1.0.0"

{
        "languageTag": "sl-Latn-IT-ROZAJ",
        "displayName": "",
        "displayName_sentenceBeginning": "",
        "displayName_uiListOrMenu": "",
        "displayName_standalone": ""
      }

Expected behavior
Should do the fallback by comparing the truncated items(language-script-territory-variant) until hit the exact matched:
language-script-territory-variant → language-script-country → language-script → language → Unknown language(Unknown ***)

sl-Latn-IT-ROZAJ should display in "sl" as below:

{
        "languageTag": "sl-Latn-IT-ROZAJ",
        "displayName": "slovenščina (latinica, Italija, rezijanščina)",
        "displayName_sentenceBeginning": "slovenščina (latinica, Italija, rezijanščina)",
        "displayName_uiListOrMenu": "slovenščina (latinica, Italija, rezijanščina)",
        "displayName_standalone": "slovenščina (latinica, Italija, rezijanščina)"
      }