Lg 10556 move error message out of flow session 1 of 2

[kbighorse]

🎫 Ticket

LG-10556

🛠 Summary of changes

This PR continues the work to remove the Flow State Machine. It replaces uses of the flow_session for errors with flash.

There will be a follow-up PR to remove code that displays flow_session error messages to the user.

📜 Testing Plan

Provide a checklist of steps to confirm the changes.

• Create account, start IDV
• On agreement step, try to continue without checking the box
• Expected result: see error under checkbox
• check box, continue to hybrid handoff
• On hybrid handoff, send link enough times to get rate limited, i.e. 6
• Expected result: see error on page in flash messages
• Create account, start IDV
• Choose hybrid flow
• Open /test/telephony in a new incognito window
• Visit hybrid link
• Cancel document upload
• Expected result: see error on link sent page in flash messages

[soniaconnolly]

LGTM. Tested and saw the flash messages when rate limited on sending links in HybridHandoff, and on canceling document capture from hybrid flow on LinkSent page.

Did not see the message on Agreement page with js turned off (doesn't show up in dev, either), but leaving that component to delete in the followup PR.