Migrate VirtualCardManualFallbackBubble test away from full server cards

This test was creating full server cards to pass into the virtual card
manual fallback bubble. This CL corrects that and passes in virtual
cards instead - which is what the real code would be doing!

Bug: 40939195
Change-Id: I36cb9666760362c596cb7ca140989dd3fe87ecfa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5808612
Reviewed-by: Olivia Saul <jsaul@google.com>
Auto-Submit: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Jan Keitel <jkeitel@google.com>
Commit-Queue: Jan Keitel <jkeitel@google.com>
Cr-Commit-Position: refs/heads/main@{#1346651}