[fips] do not expliclity set the default distro (elastic#91101)

This commit no longer explicitly sets the default configuration for FIPS tests.
This allows each project's tests to run in FIPS mode with out deviation (other
than the FIPS mode).

A side product of this change is that any REST test
can now enable security if they so choose without needing to use the default
distribution. This allows for additional usage of the integ_test distribution
which can help with testing modularization.

This only possible now that the security plugin is always included
with the integ_test distribution via elastic#77632

fixes: elastic#70005
related: elastic#77632

Author: jakelandis

build-tools-internal/src/main/groovy/elasticsearch.fips.gradle

@@ -57,7 +57,6 @@ if (BuildParams.inFipsJvm) {
           dependsOn 'fipsResources'
         }
         testClusters.configureEach {
-          setTestDistribution(TestDistribution.DEFAULT)
           extraConfigFile "fips_java.security", fipsSecurity
           extraConfigFile "fips_java.policy", fipsPolicy
           extraConfigFile "cacerts.bcfks", fipsTrustStore

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchNode.java

@@ -114,7 +114,8 @@ public class ElasticsearchNode implements TestClusterConfiguration {
         "path.repo",
         "discovery.seed_providers",
         "cluster.deprecation_indexing.enabled",
-        "cluster.initial_master_nodes"
+        "cluster.initial_master_nodes",
+        "xpack.security.enabled"
 
     );