Make naming/wording/content consistent across mobile and extension

**Problem**
There are content inconsistencies between mobile and extension that are causing users a lot of confusion and a lot of customer support tickets

Examples:

1) "assets" in extension vs "tokens" on mobile
2) "activity tab" in ext vs "txn history" on mobil

**Solution**
Establish consistent cross-product naming/wording.

Steps:
* Audit existing copy to identify inconsistencies
* Decide on consistent naming conventions
* Update copy on extension and/or mobile

Audit the existing naming and wording across the extension and mobile experiences, starting with the listed “assets”/“tokens” and “activity tab”/“txn history” examples. Establish the agreed terminology and update the affected copy in both products; done means the cross-product terminology is consistent.

Written by the indexing model from the issue text.