[Metricbeat] [GCP] Fix compute metadata (#36338)

* don't remake map

* only add instances from project_id

* fix ecs cloud region and AZ bug

* Revert "fix ecs cloud region and AZ bug"

This reverts commit 349bf6b.

* Revert "only add instances from project_id"

This reverts commit 89f6ab5.

* add changelog entry

CHANGELOG.next.asciidoc

@@ -125,6 +125,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Resolve statsd module's prematurely halting of metrics parsing upon encountering an invalid packet. {pull}35075[35075]
 - Fix the gap in fetching forecast API metrics at the end of each month for Azure billing module  {pull}36142[36142]
 - Add option in SQL module to execute queries for all dbs. {pull}35688[35688]
+- Fix GCP compute metadata. {pull}36338[36338]
 - Add support for api_key authentication in elasticsearch module  {pull}36274[36274]
 - Add remaining dimensions for azure storage account to make them available for tsdb enablement. {pull}36331[36331]
 - Add missing 'TransactionType' dimension for Azure Storage Account. {pull}36413[36413]

x-pack/metricbeat/module/gcp/metrics/compute/metadata.go

@@ -154,9 +154,6 @@ func (s *metadataCollector) instance(ctx context.Context, instanceID string) (*c
 		return computeInstance, nil
 	}
 
-	// Remake the compute instances map to avoid having stale data.
-	s.computeInstances = make(map[uint64]*computepb.Instance)
-
 	return nil, nil
 }