log `Wrote node identities dump` in sv-app

[canton-network-da]

[ This issue was auto-migrated from DA's internal repo (DACH-NY/canton-network-node#16081). Original author: @stephencompall-DA ]

What is this about?

• add confirmation log to sv-app like the one validator-app does
• include test as part of "produce backup dumps in the background"

For the sv-app we log Attempting to write node identities to GCP bucket but not a confirmation Wrote node identities dump like we do in validator-app.

splice/apps/sv/src/main/scala/org/lfdecentralizedtrust/splice/sv/SvApp.scala

Line 1279 in a982038

s"Attempting to write node identities to ${backupConfig.locationDescription} at path: $filename"

We also only test validator here; we could similarly test for sv-app's identities dump.

splice/apps/app/src/test/scala/org/lfdecentralizedtrust/splice/integration/tests/PeriodicBackupIntegrationTest.scala

Line 41 in a982038

"sv1 and alice's validator" should {

Suggested by @martinflorian-da during DACH-NY/canton-network-node#15864.

How important is this and why?

Consistency!

But also without this our internal HDM runbook isn't quite right:

https://github.com/DACH-NY/canton-network-node/blob/c5a95487d34bc7f7191f5dd4d6c20798f06dadd7/cluster/README.md#L1541