fix redis concurrency issue in health metrics + remove ongoing status count (#10717)

### Context
For calendar and message sync job health monitoring, we used to
increment a counter in redis cache which could lead to concurrency
issue.

### Solution
- Update to a set structure in place of counter + use sAdd redis method
which is atomic
- Each minute another counter was incremented on a new cache key ->
Update to a 15s window
- Remove ONGOING status not needed. We only need status at job end (or
fail).


###  Potential improvements
- Check for cache key existence before fetching data to avoid useless
call to redis ?

closes https://github.com/twentyhq/twenty/issues/10070

packages/twenty-server/src/engine/core-modules/environment/environment-variables.ts

@@ -959,7 +959,7 @@ export class EnvironmentVariables {
   @IsNumber()
   @CastToPositiveNumber()
   @IsOptional()
-  HEALTH_MONITORING_TIME_WINDOW_IN_MINUTES = 5;
+  HEALTH_METRICS_TIME_WINDOW_IN_MINUTES = 5;
 
   @EnvironmentVariablesMetadata({
     group: EnvironmentVariablesGroup.Other,