Fix wrong nodes deletion in case document contains more than 9 SNS items

The fix added in CHANNELMGR-1037 issue only expects/picks single digits:
org.onehippo.cms.channelmanager.content.document.util.FieldPath#NUMBERED_SUFFIX   

private static final Pattern NUMBERED_SUFFIX = Pattern.compile("^\\[\\d\\]$");

In case you have more than 9 SNS nodes / compounds, wrong compounds  gets deleted via channel manager. 

Here is a video for the bug: https://drive.google.com/file/d/1xZg0nLZBv_g_NjLA5k5EOSgBYufALSiA/view 

Requirements:

• Make sure org.onehippo.cms.channelmanager.content.document.util.FieldPath#NUMBERED_SUFFIX excepts two and more digits
• Make sure the customer is able to delete the compound when they have more than one digit compounds