Fix/fcm push token bug

[rgomezp]

Description

One line summary: Remove redundant retrievePushToken call and refine local model replacement logic.

Details

Motivation

Remove Unnecessary retrievePushToken Call

The retrievePushToken call in the start function has been removed. Since the config model is replaced every time, this call is redundant.

Replace Local Models with Non-Push Subscriptions

Local models are now only replaced with non-push subscriptions. The backend should sync its push token state with the client state, as the client directly obtains the token during subscription.

Testing

Manual testing

Tested locally.

• Change project number
• Send push - failed
• Open app
• Send push - success

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

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

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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This change is 

[jkasten2]

Left some comments, also looks like the failing test is due to this change and has to be updated.