Solves the problem of Explore changing the region when applying a taxon filter
on top of an existing map area or nearby filter, but also adds similar
functionality whenever the observation bounds change, e.g. for a user
filter.
* Show observations by defaulting to user location
* Remove log
* Create useHeaderCount hook to load user location count before global count
* Header count and location permission fixes
* Remove log
* Fix Explore tests
* Test fixes and add blocked/denied state
