[Vacation Delegate Invite] [FE] Replace the policy diff warning modal with an invite step page in the RHP

[rayane-d]

Part of https://github.com/Expensify/Expensify/issues/668027

Context

SetVacationDelegate with overridePolicyDiffWarning: false returns jsonCode 305 with data.policyDiff = {adminPolicies, nonAdminPolicies} (two lists of policy IDs, split by whether the requester is an admin) when the delegate is missing from some workspaces. The server writes nothing on a 305. NewDot ignores the data and only shows a generic confirm modal (VacationDelegatePage.tsx#L71-L88).

Changes

Replace the modal with a step in the RHP that renders one of three variations:

1. Admin of none (adminPolicies empty): explain that the admins will get an email. One button, "Confirm".
2. Admin of all (nonAdminPolicies empty): offer "Invite" and "Skip".
3. Admin of some (both lists filled): show both sections, offer "Invite" and "Skip".

If there is no diff, the first call sets the delegate and the step never appears. Workspace names and avatars come from the local policy_ Onyx collection.

Button	API calls	Emails
Confirm	SetVacationDelegate(overridePolicyDiffWarning=true)	sent
Invite	one AddMembersToWorkspace per admin policy, then SetVacationDelegate(overridePolicyDiffWarning=true)	sent for the non-admin workspaces in the mixed case
Skip	SetVacationDelegate(overridePolicyDiffWarning=true, skipPolicyInviteEmails=true)	none

• Add skipPolicyInviteEmails to SetVacationDelegateParams and pass it through the setVacationDelegate action.
• Read response.data.policyDiff instead of discarding it.
• "Invite" loops the existing addMembersToWorkspace action, one call per admin policy (per the bulk-action guideline and the 1:1:1 rule), then calls SetVacationDelegate.
• The 305 response merges an error object into nvp_private_vacationDelegate, so every exit path from the step must clear it.

Notes:

• skipPolicyInviteEmails is a new optional parameter on SetVacationDelegate (added in a separate backend issue). When true, the backend sets the delegate and sends no email to any workspace admin.
• On the "Confirm" and "Invite" paths, the backend emails one owner per missing workspace where the user is not an admin, with the other admins in cc, and only where the user is in that workspace's approval workflow. Admin workspaces never get an email.
• The invites should be sent before the final SetVacationDelegate, and the backend recomputes the diff, so freshly workspaces invites no longer trigger the admins emails.
• The delegate always gets their own "you are now a vacation delegate" email, including on "Skip".
• Other error codes (invalid delegate, delegate on vacation, account not found) keep the existing error modal behavior.

Issue Owner

Current Issue Owner: @war-in

[mountiny]

Jakub 🤝 Rayane 🤝 Vit

[jakubstec]

😎🙏

[rayane-d]

🤝💪🚀

[melvin-bot]

@jakubstec Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[jakubstec]

@rayane-d @mountiny
I have a question, why in the non-admin-only variation (first screen in PR description) Skip isn't available? In the mixed variation I assume it suppresses emails also for nonAdminPolicies. Is it intentional? Should the non-admin-only include Skip option, or should Skip in the mixed one still email admins of nonAdminPolicies? I see it as some possible inconsistence😄

[rayane-d]

@rayane-d @mountiny I have a question, why in the non-admin-only variation (first screen in PR description) Skip isn't available? In the mixed variation I assume it suppresses emails also for nonAdminPolicies. Is it intentional? Should the non-admin-only include Skip option, or should Skip in the mixed one still email admins of nonAdminPolicies? I see it as some possible inconsistence😄

@trjExpensify @Expensify/design, could you please clarify this? Would it make more sense to replace "Confirm" button with two explicit actions: "Ask admins to invite them" and "Skip"?