chore: create sanity checks for post release

[mosheshaham-dash0]

No description provided.

[linear-code]

CLO-485 create sanity checks for post-release

Review in Linear

[GuyMoses]

Two things:

1. Version pinning — resolve-layers picks the latest version via list-layer-versions, but there's a race condition: if another deploy lands between deploy-prod and this job, we could end up testing the wrong version. Better to pass the exact version from deploy-prod as an output so we know for sure we're testing what we just released.

2. Failure notifications — right now failures only show up in the Actions tab. Especially with the daily cron, we should have a Slack notification (or similar) on failure so we actually hear about it.

[mosheshaham-dash0]

Two things:

1. Version pinning — resolve-layers picks the latest version via list-layer-versions, but there's a race condition: if another deploy lands between deploy-prod and this job, we could end up testing the wrong version. Better to pass the exact version from deploy-prod as an output so we know for sure we're testing what we just released.
2. Failure notifications — right now failures only show up in the Actions tab. Especially with the daily cron, we should have a Slack notification (or similar) on failure so we actually hear about it.

1. not sure it's needed. sounds like a very rare case. actually, very tight releases will cause a more serious problem anyway - overrides in the stack create/destroy since we currently have only one global stack. for now i think it's good enough.
2. i've been meaning to add slack notification for all workflow failures and releases. will do so in a different PR