fix: clicking on notification sends to wrong url

[Soxasora]

Description

Partial fix of #756, 3: (clicking on notification replies sends you to really old threads)

Updates the value of url and itemId by including incoming payload's url and itemId in the merged payload.
The url that was exposed before was of the first unmerged notification, which explains navigating to really old threads

Screenshots

before:

  // incoming payload options: {"url":"/items/52742?commentId=459565","itemId":459565}
  // merged payload: {"url":"/items/458388?commentId=459556","itemId":459556,"amount":9}

after:

  // incoming payload.options.data: {"url":"/items/52742?commentId=459570","itemId":459570}
  // merged payload: {"url":"/items/52742?commentId=459570","itemId":459570,"amount":14}

Additional Context

This is part of a series of fixes tracked on #1794

Checklist

Are your changes backwards compatible? Please answer below:
Yes

On a scale of 1-10 how well and how have you QA'd this change and any features it might affect? Please answer below:
6, incoming payload is received correctly, this just updates the url inside the merged payload. Clicking on a merged notification links to the correct Item

For frontend changes: Tested on mobile, light and dark mode? Please answer below:
n/a

Did you introduce any new environment variables? If so, call them out explicitly here:
No

[Soxasora]

Merging to #1794