Provide vulnerability file language type

Why are we doing this work

Provide the file language of the vulnerability. This is currently what is provided:

The language is used to fetch the proper security training material from our vendors. This issue is part of this epic > &6176 (closed)

Why is this needed

To properly make the request to our training vendors and get the most accurate response, they require a language type as the parameter. For example java or ruby. A sample request looks like this curl -X GET 'https://application.security/api/.../search?cwe=81&language=java'. More information can be found here > https://gitlab.com/gitlab-org/gitlab/-/issues/346069#note_742608425

Relevant links

Non-functional requirements

• Documentation: Update GraphQL documentation
• Testing: Will need updated tests

Implementation plan

• backend Add file/language argument in SecurityTrainingUrlsResolver
• backend Parse the file type. May not need to use an existing class, but can see lib/gitlab/file_detector.rb or lib/gitlab/file_type_detection.rb for examples.
• backend Use the parsed language type in url finder (https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/finders/security/training_providers/base_url_finder.rb) to extract training url

Testing

• Create/update feature specs
• Counterpart SET to review changes