[POS Settings] Update link to barcode scanner docs

[iamgabrielma]

Closes WOOMOB-1227

Description

This PR updates the barcode scanner documentation link to the correct one, rather than to POS general documentation.

Steps to reproduce

• Navigate to POS > Settings > Hardware > Barcode Scanners > Tap on Documentation
• Observe the link opened is https://woocommerce.com/document/barcode-and-qr-code-scanner/

Settings	Webview

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	pr16069-5a94138
	Version	23.1
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	5a94138
	Installation URL	6m2goa5ligj4g

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[jaclync]

Works nicely

Nit in dark mode, the selected light purple color feels a bit close to the white text color. Maybe we could use a purple color that has more contrast from the text color in dark mode?

[jaclync]

nit: from Povilas's effort to modularize POS, I wonder if we could separate the POS constants so that the POS code isn't dependent on the constants enums that are mostly used in the store management part of the app.

[iamgabrielma]

Thanks for pointing that out, I've made a POSConstants on 2990f6b which copies the current usage of WooConstants, and moved the 2 documentation links we use for settings along with 4bb6fc5

Most likely we'll want to copy over as well the links regarding IPP, but I'll leave it out for the moment.

[iamgabrielma]

Thanks for the review!

Nit in dark mode, the selected light purple color feels a bit close to the white text color. Maybe we could use a purple color that has more contrast from the text color in dark mode?

Yeah, this is something we brought up to design, as the dark version of the selection only works well when text is not primary. Today we should be clear on which one to use for i1. We also asked for dark versions of all views for next iteration to avoid these issues in the future 👍

[iamgabrielma]

Nit in dark mode, the selected light purple color feels a bit close to the white text color. Maybe we could use a purple color that has more contrast from the text color in dark mode?

Updated the selection color on a different PR where it made more sense in context: #16070 👍