Added FileDisclosure vulnerability enhancements

What does this MR do?

Enhanced sast-rule java/inject/rule-FileDisclosure.yml

• Removed org.apache.struts.action.ActionForward patterns because it is struts 1 which was EOL'd in 2008.
• Splited the rules into two files: rule-FileDisclosureRequestDispatcher and rule-FileDisclosureSpringFramework
• Fixed descriptions for each rule file
• Fixed mappings
• Added new pattern-sources
• Updated the sample java code files

What are the relevant issue numbers?

Issue - 433056

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer