This updates the gradle wrapper to 8.12
We addressed deprecation warnings due to the update that includes:
- Fix change in TestOutputEvent api
- Fix deprecation in groovy syntax
- Use latest ospackage plugin containing our fix
- Remove project usages at execution time
- Fix deprecated project references in repository-old-versions
* Modularize shard availability service
This commit moves the `ShardsAvailabilityHealthIndicatorService` to a package and modularizes it
with exports so that Serverless can make use of it as a superclass.
Relates to #101394
* Make the ShardsAvailabilityIndicator pluggable
This commit makes the `ShardsAvailabilityIndicator` pluggable. It currently provides the existing `ShardsAvailabilityHealthIndicatorService` (without moving it) for the `shards_availability` output in the health report API.
This will allow us in the future to provide a separate `shards_availability` plugin to override the way that health is reported for shards.
