docs: fix JWT plugin frontmatter formatting across all versions

[wy471x]

Summary

Fixed malformed frontmatter across all 20 JWT plugin documentation files in the project.

Problem

Each file had two frontmatter issues:

1. A blank line between the opening --- delimiter and the title field
2. A line of dashes used as the closing delimiter instead of ---

Before

---
title: JWT plugin
keywords: ["JWT"]
description: JWT plugin
-----------------------

After

---
title: JWT plugin
keywords: ["JWT"]
description: JWT plugin
---

Affected Files

Chinese (i18n/zh/) — 14 files

Version	File
current	i18n/zh/docusaurus-plugin-content-docs/current/plugin-center/security/jwt-plugin.md
2.4.0	i18n/zh/docusaurus-plugin-content-docs/version-2.4.0/plugin-center/authority-and-certification/jwt-plugin.md
2.4.1	i18n/zh/docusaurus-plugin-content-docs/version-2.4.1/plugin-center/authority-and-certification/jwt-plugin.md
2.4.2	i18n/zh/docusaurus-plugin-content-docs/version-2.4.2/plugin-center/authority-and-certification/jwt-plugin.md
2.4.3	i18n/zh/docusaurus-plugin-content-docs/version-2.4.3/plugin-center/authority-and-certification/jwt-plugin.md
2.5.0	i18n/zh/docusaurus-plugin-content-docs/version-2.5.0/plugin-center/security/jwt-plugin.md
2.5.1	i18n/zh/docusaurus-plugin-content-docs/version-2.5.1/plugin-center/security/jwt-plugin.md
2.6.0	i18n/zh/docusaurus-plugin-content-docs/version-2.6.0/plugin-center/security/jwt-plugin.md
2.6.1	i18n/zh/docusaurus-plugin-content-docs/version-2.6.1/plugin-center/security/jwt-plugin.md
2.7.0	i18n/zh/docusaurus-plugin-content-docs/version-2.7.0/plugin-center/security/jwt-plugin.md
2.7.0.1	i18n/zh/docusaurus-plugin-content-docs/version-2.7.0.1/plugin-center/security/jwt-plugin.md
2.7.0.2	i18n/zh/docusaurus-plugin-content-docs/version-2.7.0.2/plugin-center/security/jwt-plugin.md
2.7.0.3	i18n/zh/docusaurus-plugin-content-docs/version-2.7.0.3/plugin-center/security/jwt-plugin.md
2.7.1	i18n/zh/docusaurus-plugin-content-docs/version-2.7.1/plugin-center/security/jwt-plugin.md

English (versioned_docs/) — 6 files

Version	File
2.4.0	versioned_docs/version-2.4.0/plugin-center/authority-and-certification/jwt-plugin.md
2.4.1	versioned_docs/version-2.4.1/plugin-center/authority-and-certification/jwt-plugin.md
2.4.2	versioned_docs/version-2.4.2/plugin-center/authority-and-certification/jwt-plugin.md
2.4.3	versioned_docs/version-2.4.3/plugin-center/authority-and-certification/jwt-plugin.md
2.5.0	versioned_docs/version-2.5.0/plugin-center/security/jwt-plugin.md
2.5.1	versioned_docs/version-2.5.1/plugin-center/security/jwt-plugin.md