Need to use serial comma in 3rd sentence in `Chat Privately with Brave Leo` disclaimer

[stephendonner]

Description

Need to use serial comma in 3rd sentence in Chat Privately with Brave Leo disclaimer

Steps to reproduce

1. install 1.70.3
2. launched Brave
3. clicked on Leo in the sidebar
4. read the 3rd sentence of the disclaimer text after clicking Summarize this page

Actual result:

...offers more models, higher limits and gives subscribers...

From our Style Guide:

Expected result:

...offers more models, higher limits, and gives subscribers...

Reproduces how often

Easily reproduced

Brave version (brave://version info)

Brave | 1.70.3 Chromium: 127.0.6533.57 (Official Build) nightly (x86_64)
-- | --
Revision | 5cffaa4489061c923503422bf71a1d1ff55a6e86
OS | macOS Version 11.7.10 (Build 20G1427)

Channel information

• [X] release (stable)
• [X] beta
• [X] nightly

Reproducibility

• [X] with Brave Shields disabled
• [X] with Brave Rewards disabled
• [ ] in the latest version of Chrome

Miscellaneous information

/cc @macauleyberg @rmcfadden3 @mattmcalister @nullhook @petemill @bbondy

[stephendonner]

cc @brave/qa-team and @rebron

[stephendonner]

@Uni-verse @hffvld I didn't bring my mobile devices with me on this trip: I take it this is shared WebUI, and exists on mobile too? If so, mind sprinkling the labels? 🙇