### Description

**Background**
As part of https://github.com/elastic/kibana/issues/104986 we will be adding the ability for Elastic Agents to send agent monitoring data to a remote Elasticsearch cluster. In order to achieve this, we will need a service token for the remote cluster which fleet server will use. 

This service account will need less permissions than the `elastic/fleet-server` as integration data will not be sent to remote clusters yet.

**Service Account Details**

Name: `elastic/fleet-server-remote`

Permissions:
-  for indices `logs-*`, `metrics-*` privileges "write", "create_index", "auto_configure"

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/service/ServiceAccountServiceTests.java
appender.start();
        try {
            
            appender.addExpectation(
                new MockLogAppender.SeenEventExpectation(
                    "less than 4 bytes",
                    ServiceAccountToken.class.getName(),
                    Level.TRACE,
                    "service account token expects the 4 leading bytes"
                )
            );
            final SecureString bearerString0 = createBearerString(List.of(Arrays.copyOfRange(magicBytes, 0, randomIntBetween(0, 3))));
            assertNull(ServiceAccountService.tryParseToken(bearerString0));
            appender.assertAllExpectationsMatched();
            
            appender.addExpectation(
                new MockLogAppender.SeenEventExpectation(
                    "prefix mismatch",
                    ServiceAccountToken.class.getName(),
                    Level.TRACE,
                    "service account token expects the 4 leading bytes"
                )
            );
            final SecureString bearerString1 = createBearerString(
                List.of(
                    new byte[] { randomValueOtherThan((byte) 0, ESTestCase::randomByte) },
                    randomByteArrayOfLength(randomIntBetween(30, 50))
                )
            );
            assertNull(ServiceAccountService.tryParseToken(bearerString1));