Add POS Go pattern

[tiannafischer]

Fixes shopify/boot-to-shopify#1509

Description of change

Adding patterns to identify POS Go devices per this ticket.

Why did you choose this approach?

The browser sniffer uses the user agent to identify the browser, OS, and device.

The browser on POS Go uses a custom user agent that can be identified by the model name WSC6X. This model name has been used to identify user agent strings containing WSC6X as the browser on POS Go.

For more context, see this discussion

What should reviewers focus on?

I'm open to suggestions about how things are named. Names will be returned as follows:

• Browser name: Shopify POS Go
• OS name: Shopify Retail OS
• Device name: Shopify POS Go

The browser name was chosen to make sure that it is easy to identify a login on a POS Go device from https://accounts.shopify.com/accounts/.../security. Logins are displayed here as "Browser name on OS name" (e.g., "Shopify POS Go on Shopify Retail OS"

Before you merge

• The changes covered by automated tests (e.g. unit, E2E)

[smjackson]

BBPOS is changing the string to WTH1X in the next ROM so we may want to also match on that string to get ahead of the problem.

[tiannafischer]

Done!

[LeoKaliazine]

They are, but we may not be, since analytics relies on this value as is we were considering hardcoding it to stay the same in the user agent...
Don't remember what decision we made, but until we make the change in our UA or at least test that the ROM level change will actually even effect the value we fetch for the UA...
Let's sync on this.

[rafaelsteil]

@LeoKaliazine Not sure if I follow. The UA identified here will be WSC6X and WTH1X, so there should be no impact on Mode (as the changes there are independent from this one)

[LeoKaliazine]

Oh sorry, was focused more on the comment than the code, yeah having both works 👍🏻