Skip FIPS JVMs in testReloadCredentialsFromKeystore (elastic#116814)

This test doesn't need to run in FIPS mode, and apparently it fails
sometimes, so with this commit we skip it.

Closes elastic#116811

(cherry picked from commit ea90fbc)

# Conflicts:
#	muted-tests.yml

modules/repository-s3/src/javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3RestIT.java

@@ -52,6 +52,8 @@ protected String getTestRestCluster() {
     }
 
     public void testReloadCredentialsFromKeystore() throws IOException {
+        assumeFalse("doesn't work in a FIPS JVM, but that's ok", inFipsJvm());
+
         // Register repository (?verify=false because we don't have access to the blob store yet)
         final var repositoryName = randomIdentifier();
         registerRepository(