[Feat] Show iOS supported message

[jkasten2]

Description

1 Line Summary

Improve DX for not supported browser since it can be confusing for iOS.

Details

Validation

Tests

Tested to ensure new "...To support iOS please install as a Web App. See the OneSignal guide https://documentation.onesignal.com/docs/safari-web-push-for-ios" shows on an iPhone running iOS 16.7.2 in the JS console when using Safari.

Info

Checklist

• All the automated tests pass or I explained why that is not possible
• I have personally tested this on my machine or explained why that is not possible
• I have included test coverage for these changes or explained why they are not needed

Programming Checklist
Interfaces:

• Don't use default export
• New interfaces are in model files

Functions:

• Don't use default export
• All function signatures have return types
• Helpers should not access any data but rather be given the data to operate on.

Typescript:

• No Typescript warnings
• Avoid silencing null/undefined warnings with the exclamation point

Other:

• Iteration: refrain from using elem of array syntax. Prefer forEach or use map
• Avoid using global OneSignal accessor for context if possible. Instead, we can pass it to function/constructor so that we don't call OneSignal.context

Screenshots

Info

Checklist

• I have included screenshots/recordings of the intended results or explained why they are not needed

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Related Tickets

Fixes #1126

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This change is