[Gen 2] Migrate Working with Files to Swift

[chrisbonifacio]

Description of changes:

Adds inline filters for Swift examples of working with files

Related GitHub issue #, if available:

Instructions

If this PR should not be merged upon approval for any reason, please submit as a DRAFT

Which product(s) are affected by this PR (if applicable)?

• amplify-cli
• amplify-ui
• amplify-studio
• amplify-hosting
• amplify-libraries

Which platform(s) are affected by this PR (if applicable)?

• JS
• Swift
• Android
• Flutter
• React Native

Please add the product(s)/platform(s) affected to the PR title

Checks

• Does this PR conform to the styleguide?

• Does this PR include filetypes other than markdown or images? Please add or update unit tests accordingly.

• Are any files being deleted with this PR? If so, have the needed redirects been created?

• Are all links in MDX files using the MDX link syntax rather than HTML link syntax?
  
  ref: MDX: [link](https://docs.amplify.aws/)
  HTML: <a href="https://docs.amplify.aws/">link</a>

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• Ready to merge

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[lawmicha]

Thanks for the work on this, there are just a minor discrepancy remaining. The important part is done, which is migrating from key to path in the examples. the examples provide context to the reader while the full example is what would make sense for the reader to copy over (since it has a lot going on, the UI components, view models, etc). but they are not updated to the path. To summarize

• the full example code should be updated to use path instead of key
• the full example code has methods like createSong(name: String, artCover: UIImage) whose content is directly copied as the top level examples on this page. we should keep the full example code and the individual code snippets aligned
• can optimize removal of guard by using get(). (optional improvement)
• remove force unwrapping