v1.x: Change example app cookies to use SameSite=Lax

[kmjennison]

Cherry-pick of #354 for v1.x.

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/gladly-team/nfa-example/DStP3kiT8mQJLScNqUSyTaiRtUtf
✅ Preview: https://nfa-example-git-kevin-v1-example-cookie-lax-gladly-team.vercel.app

[codecov]

Codecov Report

Merging #360 (1f49b76) into v1.x (943e221) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             v1.x     #360   +/-   ##
=======================================
  Coverage   99.59%   99.59%           
=======================================
  Files          25       25           
  Lines         497      497           
  Branches      178      178           
=======================================
  Hits          495      495           
  Misses          2        2           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 943e221...1f49b76. Read the comment docs.