Fixes noticed during user testing(part-1) (#3450)

Refs: #3448 

- [ ] PAF waiting for approval table shouldn't show if no project in any
tab.
- [ ] Show requested by as well in PAF Approvals(sidebar). Right now
only Pending and Approved are showing.
- [ ] Show activities on the Invoice page.
- [ ] Remove converted status from Invoices.
- [ ] Format price to US format(configurable via settings)
- [ ] "Add Invoice' as next step even after invoice creation(remove next
step after one invoice).
- [ ] Add section id to comments and use those for scrolling(request
change comments)