Problem

TravelDomainListItem takes an isRecommended boolean on its item type and uses it purely to decide whether to render a child component — a Badge:

• src/components/SelectionList/ListItem/TravelDomainListItem.tsx:21 — the flag declaration
• src/components/SelectionList/ListItem/TravelDomainListItem.tsx:44 — const showRecommendedTag = item.isRecommended ?? false;
• src/components/SelectionList/ListItem/TravelDomainListItem.tsx:68 — {showRecommendedTag && <Badge text={translate('travel.domainSelector.recommended')} />}

This is configuration, not data. It also drags a travel-specific concern (the travel.domainSelector.recommended copy and the Badge import) into the shared SelectionList/ListItem layer, which is exactly what [$1000] [Tracking] SelectionList ListItem - Composition over Configuration is decomposing away.

Scope

There is exactly one consumer, so this is a small, self-contained change:

• src/pages/Travel/EnableTravel/subPages/DomainSelectorStep.tsx:22 — isRecommended: boolean on DomainItem
• src/pages/Travel/EnableTravel/subPages/DomainSelectorStep.tsx:40 — isRecommended: domain === recommendedDomain

Proposed direction

Delete isRecommended and let the page own the badge. Two options worth weighing in the PR:

1. Compose the row at the call site. DomainSelectorStep builds the row from SelectableListItem + ListItemComposed.Title + its own Badge, and TravelDomainListItem is either deleted from src/components/SelectionList/ListItem/ or moved next to the travel page as a local row. This keeps the shared ListItem layer free of travel copy.
2. Pass the element as data. The page sets the Badge element on the item (actionElement / rightElement — the slots at ListItem/types.ts:60-66) and the shared row renders whatever it is given. Less churn, but the badge sits in the data array rather than in JSX.

Option 1 matches the composition direction in the tracking issue; option 2 is the cheaper fallback if the badge must stay inline between the title and the row end.

Acceptance criteria

• isRecommended no longer exists on any SelectionList ListItem type.
• Badge and travel.domainSelector.recommended are no longer referenced from src/components/SelectionList/.
• The domain selector still shows the "Recommended" badge on the most frequent admin email domain, and only on that row.
• Existing tests for the travel domain selector still pass, with coverage added for the composed row.

Context

Follow-up from roryabraham's review comment on SelectionList ListItem decomposition - sweep and flag deletion, raised as NAB because the prop already existed.

Part of [$1000] [Tracking] SelectionList ListItem - Composition over Configuration.