libbeat: increase total_fields.limit to 12500 (#41640)

* libbeat: increase index template total_fields.limit to 12500

It increased the `index.mapping.total_fields.limit` from `10000` to `12500` in order to avoid ingestion failures caused by too many field in the index. Since 8.15.0 the limit started to be hit.
The field count being exceeded is on the index, counting all mapped fields and the dynamic fields. That's why a small event might trigger the error, the event contains new fields to be mapped which would exceed the total field limit if mapped.

(cherry picked from commit 42dd93b)

# Conflicts:
#	CHANGELOG.asciidoc

Author: AndersonQ

CHANGELOG.asciidoc

@@ -110,6 +110,7 @@ https://github.com/elastic/beats/compare/v8.15.3\...v8.15.4[View commits]
 *Affecting all Beats*
 
 - Fix issue where old data could be saved in the memory queue after acknowledgment, increasing memory use. {pull}41356[41356]
+- Fix metrics not being ingested, due to "Limit of total fields [10000] has been exceeded while adding new fields [...]". The total fields limit has been increased to 12500. No significant performance impact on Elasticsearch is anticipated. {pull}41640[41640]
 
 *Filebeat*
 
@@ -212,6 +213,10 @@ https://github.com/elastic/beats/compare/v8.15.0\...v8.15.1[View commits]
 
 *Affecting all Beats*
 
+<<<<<<< HEAD
+=======
+- Beats Docker images do not log to stderr by default. The workaround is to pass the CLI flag `-e` or to set `logging.to_stderr: true` in the configuration file.
+>>>>>>> 42dd93b99b (libbeat: increase total_fields.limit to 12500 (#41640))
 - Beats stop publishing data after a network error unless restarted. Avoid upgrading to 8.15.1. Affected Beats log `Get \"https://${ELASTICSEARCH_HOST}:443\": context canceled` repeatedly. {issue}40705{40705}
 
 ==== Bugfixes

libbeat/template/load_test.go

@@ -170,7 +170,7 @@ func TestFileLoader_Load(t *testing.T) {
 							"refresh_interval": "5s",
 							"mapping": mapstr.M{
 								"total_fields": mapstr.M{
-									"limit": 10000,
+									"limit": defaultTotalFieldsLimit,
 								},
 							},
 							"query": mapstr.M{

libbeat/template/template.go

@@ -35,7 +35,7 @@ import (
 var (
 	// Defaults used in the template
 	defaultDateDetection           = false
-	defaultTotalFieldsLimit        = 10000
+	defaultTotalFieldsLimit        = 12500
 	defaultMaxDocvalueFieldsSearch = 200
 
 	defaultFields []string