Bandwidth Graph Anomaly in Brave

> Part of an effort to run embedded js-ipfs in Brave :lion: https://github.com/ipfs-shipyard/ipfs-companion/issues/716

### Problem

While working on [js-ipfs in Brave](https://github.com/ipfs-shipyard/ipfs-companion/issues/664) I noticed embedded HTTP API exposed by js-ipfs produced buggy graph (note "s" on the left axis on screens below).

### js-ipfs 0.35.0-rc.5

Sample graph from Brave:
> 
Sample js-ipfs response for `/api/v0/stats/bw`:
> ```json
> {"TotalIn":"31848851","TotalOut":"1440904","RateIn":"6.158484647860612","RateOut":"5.028479187074011"}
> ```

### go-ipfs 0.4.19

Sample graph from Brave:
> 
>
> Sample go-ipfs response for `/api/v0/stats/bw`:
> ```json
> {"TotalIn":183758816,"TotalOut":355038782,"RateIn":5376.543583100996,"RateOut":9682.160239299323}
> ```
----

### Reproducibility

Did some testing and this issue occurs in regular [Brave Beta](https://brave.com/download-beta/) using vanilla Web UI. Interestingly, the problem does not show on Google Chrome Beta, looking at the same Web UI+API produces normal graph. I tested this on two linux machines.

#### Versions

- Web UI version: `QmfQkD8pBSBCBxWEwFSu4XaDVSWK6bjnNuaWZjMyQbyDub` (v2.4.4)
- Brave versions: 0.61, 0.63.35 :anger: (issue seen on screenshots below)
- Firefox version: 66 :angel: (works ok)
- Google Chrome version: 73.0 :angel: (works ok)

Is anyone else using Brave and can confirm this is a real issue and not something on my end?
(The ask is to open Web UI in Brave via menu item in IPFS Companion)