Channel branding sed in trivalent.spec has been a no-op since M143

This line no longer matches anything:

```spec
sed -i 's/getenv("CHROME_VERSION_EXTRA")/"%{chromium_name}"/' chrome/common/channel_info_posix.cc
```
Since it exits 0, it has been silently failing since Chromium 143.0.7499.95, when the `getenv` calls were consolidated into a single helper. So with `CHROME_VERSION_EXTRA` unset, the channel name resolves to an empty string