Pass partition config and isolation group to history/matching even if…

… isolation is disabled (#5385)

What changed?
Pass partition config and isolation group to history/matching even if isolation is disabled

Why?

This will expose the distribution of tasks among different isolation groups even if isolation is not enabled, and let us know if there is any skewness in the traffic before enabling isolation
This will allow history persisting partition config and if isolation can take effect immediately for existing workflows
How did you test it?
manual test

Potential risks

Release notes

Documentation Changes

service/frontend/workflowHandler.go

@@ -788,17 +788,11 @@ func (wh *WorkflowHandler) PollForDecisionTask(
 }
 
 func (wh *WorkflowHandler) getIsolationGroup(ctx context.Context, domainName string) string {
-	if wh.config.EnableTasklistIsolation(domainName) {
-		return partition.IsolationGroupFromContext(ctx)
-	}
-	return ""
+	return partition.IsolationGroupFromContext(ctx)
 }
 
 func (wh *WorkflowHandler) getPartitionConfig(ctx context.Context, domainName string) map[string]string {
-	if wh.config.EnableTasklistIsolation(domainName) {
-		return partition.ConfigFromContext(ctx)
-	}
-	return nil
+	return partition.ConfigFromContext(ctx)
 }
 
 func (wh *WorkflowHandler) isIsolationGroupHealthy(ctx context.Context, domainName, isolationGroup string) bool {