Html sanitizer repeatedly adds rel="noopener noreferrer" even if it's pre-exist

[anudhuri23]

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### So we are using OWASP/java-html-sanitizer to sanitize the html. It adds noopener noreferrer everytime we sanitize it. It should not add noopener noreferrer if it's already exists in the HTML.

Also note that we have already upgraded the jar to latest one i.e owasp-java-html-sanitizer-20220608.1.jar

For bugs, please include
Input

```
<p dir="ltr"><a href="http://bbbbb" rel="noopener noreferrer" target="_blank">www.bbbbbbb.com</a></p>
```

Output I am getting right now

```
<p dir="ltr"><a href="http://bbbbb" rel="noopener noreferrer noopener noreferrer" target="_blank">www.bbbbbbb.com</a></p>
```

Expected output

```
<p dir="ltr"><a href="http://bbbbb" rel="noopener noreferrer" target="_blank">www.bbbbbbb.com</a></p>
```

### Note
I found similar issue #145 here which is very old issue but it's not resolved yet. Hence creating new one. Please help me on resolving it. It's urgent

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[mikesamuel]

Fixed in e8aa0f1