Correctly count nri uid request counts

Correctly count nri uid request counts in the per-app functionality in
connectivity currently used by set profile and set oem network
preference APIs. Previously, upon creation, nris would be created prior
to removing them. This would cause the uid request counts to
artificially increase and incorrectly throw an error if the request
count limit was hit even though in actuality an apps request count was
valid.

E.g., if there was an existing request for per-app functionality and
its owning app made a change to the per-app requests, it would double
count the existing requests. If the current count was say, one under the
limit, an error would be thrown even though it was being replaced which
should have resulted in no net change to the request count limit if
working correctly.

This patch will allow for the requests to be removed prior to creation
so that request counts are tabulated correctly.

Bug: 185849563
Bug: 183785319
Test: atest FrameworksNetTests
Change-Id: I13da0c81256cc02bea6aff2fe1ef99d6f6b0e764