CHNL-14775: Add badge incrementing logic to extension + README

[belleklaviyo]

Description

SDK changes: CHNL-14775
README updates: CHNL-12941

Adding handling of new push payloads to service extension. Modifies the autoclearing set up, so it is on by default. Devs can disable it by adding a key in their Info.plist. README updated.

Check List

• Are you changing anything with the public API?
• Have you tested this change on real device?
• Are your changes backwards compatible with previous SDK Versions?
• Have you added unit test coverage for your changes?
• Have you verified that your changes are compatible with all the operating system version this SDK currently supports?

Manual Test Plan

Pre-reqs (new steps in README):

1. Set up App Group for Notification Service Extension and main app target with the same name (e.g. group.com.klaviyo.SDKTestApp.shared)
2. Add Klaviyo_App_Group to both the main app target's and the extension's Info.plists with the name of the App Group

Default Autoclearing

1. Send some plain notification from Push Notification Console to populate the badge count (i.e. badge = 3 in payload) with the app in the background and observe badge of 3

{
    "aps": {
        "alert": {
            "title": "title",
            "subtitle": "subtitle",
            "body": "body"
        },
        "badge": 3
    }
}

3. Open the app
4. Close the app and observe badge cleared to 0

Disabling Autoclearing

1. Add disable_Klaviyo_badge_autoclearing to the Info.plist of the main app target as a Boolean set to YES (as defined in the README)
2. Send some plain notification from Push Notification Console to populate the badge count (i.e. badge = 3 in payload) with the app in the background and observe badge of 3
3. Open the app
4. Close the app and observe badge of 3 still remains

Push Notification Console Testing
Send payloads as documented here to cover all possible paths of badge configurations:

• badge:off
• badge:on, config:increment_one, value:1
• badge:on, config:set_count, value:3 (or any valid int value)
• badge:on, config:set_property, value:5 (or any valid int value)

Note: only other non happy paths worth testing imo are where we are sending the badge_config but no badge_value due to poor rendering and if there were some new enum case added on the backend and the SDK is not updated:

• badge:on, config:increment_one, NO VALUE
• badge:on, config:set_count, NO VALUE
• badge:on, config:set_property, NO VALUE
• badge:on, config:ex_new_enum, NO VALUE
• badge:on, config:ex_new_enum, value:2 (or any valid int value)

End to End Testing

Supporting Materials

[kennyklaviyo]

nit: can we run this whole readme thru copilot to correct any grammatical issues/inconsistency in wording?