Draft: probe content type of files using different strategy (i.e. inspect first bytes)

[HoneyryderChuck]

current implementations are relying on file name/extension, which is prone to errors (.mp4, is it a video or a picture?) and spoofing. This change allows customers to use or opt into mechanisms which inspect the first bytes of a file's payload.

I'd like to do the same change for other http clients we use, but I'd like to feedback to validate the viability of this approach first.

PR checklist

• [x] Read the contribution guidelines.
• [x] Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• [ ] Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH) Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
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[HoneyryderChuck]

cc @martin-mfg @lwlee2608

[wing328]

https://github.com/OpenAPITools/openapi-generator/actions/runs/9585429177/job/26431446540?pr=18949

please update the samples when you've time