Update the header name in Track expense, Submit expense, and Split expense

[kevinksullivan]

As part of the Add split to global create doc, and specifically this section, we are updating the header for the Track expense, Submit expense, and Split expense flows, to keep that title in the header for the whole flow instead of updating the header to show the "type" of track/request/split the person is creating (like manual).

Here is an example from Split, where you'll see the header is Split expense throughout.

Let's make this update to each of the mentioned flows.

[shubham1206agra]

Handling the changes in #40576

[melvin-bot]

@mountiny, @shubham1206agra, @getusha Eep! 4 days overdue now. Issues have feelings too...

[getusha]

deployed to production last week

[getusha]

We can close this @mountiny