New tab stats don't update when you go back

[bird]

Description

If you open a new tab, and go to a site, then hit back, all the stats will show as 0 (Trackers blocked, Ads blocked, etc)

Steps to Reproduce

1. With new tab page enabled open a new tab
2. Note the correct amount of Trackers/Ads/etc. blocked.
3. Navigate to any page
4. Hit the back button and note all amounts showing 0.

Actual result:

Expected result:

Reproduces how often:

Reproduces 100% of time

Brave version (brave://version info)

Brave	0.55.20 Chromium: 70.0.3538.67 (Official Build) (64-bit)
Revision	9ab0cfab84ded083718d3a4ff830726efd38869f-refs/branch-heads/3538@{#1002}
OS	Windows

Reproducible on current release:

Reproduces on current release channel

Website problems only:

Brave shield should not have an effect as it is not enabled on new tab, and chrome does not have this feature so that is irrelevant.

Additional Information

N/a

[srirambv]

Dupe of #307