Skip showing OS version in device list if the value is a frozen token

[janbrasna]

Description

"Connected Services" device list contains some user agent data that's no longer updated by the browsers/OSes, resulting in confusing device list to users unaware of that gotcha.

Steps to reproduce

Sign in using W11, macOS 11+, iPad in "dektop mode" or iOS 26+

Expected result

Correct device OS is shown, or, when in doubt, no specific OS version listed.

Actual result

User–agent HTTP header–based identification is shown, confusing users — as these OS/platform values have been frozen in browsers for a long time, so users randomly report "Firefox not recognizing I've updated to W11, how do I install the correct version instead of this W10" or "somebody with iOS 18.7 has access to my account please help" kind of woes just based on the UAstring parsing cap limitations.

Environment

macOS 12+15, iPadOS 18+26; + reporters regularly W11 getting confused by W10 devices listed.

This is my macOS 12, and the iOS "Safari" entries are actually FxA SSO into native apps (think VPN) using the in–app webview flow.	This user is on Windows 11, not Windows 10; however both browsers cap Win NT version in UA.

┆Issue is synchronized with this Jira Task

[sreecharan-desu]

hey @vpomerleau — could i get this assigned?

the connected services list is still showing frozen ua versions (win11 as win10, stale ios/macos). there's already toGenericOSName in settings; i'd look at dropping the version when it's one of those capped tokens.

[janbrasna]

FYI this applies to not only the dashboard, but also to any "new device login" emails that too include the OS details:

fxa/libs/accounts/email-renderer/src/partials/userDevice/index.txt

Lines 1 to 14 in a87e6a5

	<% const { uaBrowser, uaOS, uaOSVersion } = device; %>
	<% if (uaBrowser) { %>
	<% if (uaOS) { %>
	<% if (uaOSVersion) { %>
	device-all = "<%- `${uaBrowser} on ${uaOS} ${uaOSVersion}` %>"
	<% } else { %>
	device-browser-os = "<%- `${uaBrowser} on ${uaOS}` %>"
	<% } %>
	<% } else { %>
	<%- uaBrowser %>
	<% } %>
	<% } else { %>
	<%- uaOS %><% if (uaOSVersion) { %> <%- uaOSVersion %><% } %>
	<% } %>

[sreecharan-desu]

@janbrasna good catch — yeah, the new-device login emails would show the same frozen ua (win11 as win10, stale ios/macos).

i'll include the userDevice email partial in the same change so the dashboard and those emails stay consistent.