[swift] to support application/octet-stream for file upload

[wing328]

based on #15140

credits: @aniruddhJo

cc @antihax (2017/11) @grokify (2018/07) @kemokemo (2018/09) @jirikuncar (2021/01) @ph4r5h4d (2021/04) @lwj5 (2023/04)

PR checklist

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• Run the following to build the project and update samples:

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

  Commit all changed files.
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  ./bin/utils/ensure-up-to-date
  

  Commit all changed files.
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