Drop minimum OS requirements to minimum currently supported by Apple

[matux]

Description of the change

Our OS minimum requirements are unnecessarily high, this makes certain configuration aspects and integration instructions overly difficult.

This guarantees no extra configuration or changes are necessary when integrating the Apple SDK, whether directly, or through other SDKs like the Flutter SDK and the React Native SDK.

It also guarantees no restrictions to minimum supported OS are forced upon clients.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Maintenance
• New release

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers assigned
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer