default @Nullable String getPrefix() {
        return queryPrefix().result();
    }
Gets the prefix.

<p>This method uses the rules defined by the {@link #getPrefixStackDefinition() prefix stack}
to produce a {@link String} output.</p>

<p>Assuming the default configuration is used, this will usually be the value of the
holder's highest priority prefix node.</p>

<p>If the resultant prefix stack contained no elements, {@code null} is returned.</p>

@return a prefix string, or null
api/src/main/java/net/luckperms/api/cacheddata/CachedMetaData.java