Remove duplicate permissions (opensearch-project#3690)

### Description
Permission: `permission java.util.PropertyPermission "*", "read,write";`
was declared twice. Observed here:
opensearch-project#3671
I will backport it in my PR.

### Testing
[Please provide details of testing done: unit testing, integration
testing and manual testing]

### Check List
- [ ] New functionality includes testing
- [ ] New functionality has been documented
- [ ] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and
signing off your commits, please check
[here](https://github.com/opensearch-project/OpenSearch/blob/main/CONTRIBUTING.md#developer-certificate-of-origin).

Signed-off-by: Andrey Pleskach <[email protected]>

plugin-security.policy

@@ -34,6 +34,8 @@ grant {
   permission javax.security.auth.AuthPermission "modifyPrivateCredentials";
   permission javax.security.auth.AuthPermission "doAs";
   permission javax.security.auth.kerberos.ServicePermission "*","accept";
+
+  //SAML and internal plugin policy
   permission java.util.PropertyPermission "*","read,write";
 
   //Enable when we switch to UnboundID LDAP SDK
@@ -74,8 +76,6 @@ grant {
   //Enable this permission to debug unauthorized de-serialization attempt
   //permission java.io.SerializablePermission "enableSubstitution";
 
-  //SAML policy
-  permission java.util.PropertyPermission "*", "read,write";
 };
 
 grant codeBase "${codebase.netty-common}" {