Finalizing styling and variable injection for Key Insights component

[jessex]

What needs to be done? Why does it need to be done? Finish the implementation of the Key Insights component:

• Ensure that data can be injected into the component and inserted into the various strings of dynamic text correctly
• Ensure that styling of dynamic vars is correct, e.g. the colored difference percentages (-16%) and the main numbers (-3,075)
  • This includes rounding of percentages, inserting commas into numbers, setting the right size/boldness/color,

Additional context See more about this in the PRD and the mocks

[jessex]

@Wmaileq, I just spoke with Product and they let me know they intend to actually bring back the Key Insights component. It will probably be mostly the same as what you had previously built but they will update the PRD soon with specifics. But if you need something to do, a PR that brings that component back in its current form and makes sure it's fully up-to-date with the latest in the app would be wise.