Issue Summary

When disabling Widget Connector and pasting a youtube link into a Confluence page, the link will immediately disappear. It seems the widget connector has to be enabled

Earlier versions of Confluence such as v 5.10.9 Individual modules could be disabled in the Confluence Paste to prevent auto converting to the Widget Connector using the steps from How to Turn Off Autoconvert

Steps to Reproduce

1. disable widget connector
2. Insert youtube link into a confluence page

To disable auto converter, (which resolves this in older versions) in a newer version of Confluence the following steps can be used:

to force disable the auto covert widget connector from Confluence Paste, spin up a version of Confluence (5.10.9) that allows for disabling the modules for Confluence Paste and getting the output from this query:

select BANDANAVALUE from BANDANA where BANDANAKEY = 'plugin.manager.state.Map';

Take this output and put into a newer instance such as 7.2.1 instance with the following query:

UPDATE BANDANA
SET BANDANAVALUE = '<map>
  <entry>
    <string>com.atlassian.confluence.plugins.confluence-software-blueprints:jira-sprints-item</string>
    <boolean>true</boolean>
  </entry>
  <entry>
    <string>com.atlassian.confluence.plugins.confluence-paste:autoconvert-widget-connector</string>
    <boolean>false</boolean>
  </entry>
</map>'
WHERE BANDANAKEY = 'plugin.manager.state.Map';

Restart confluence and cleared the plugins cache and this forced disabled that module.

Expected Results

Link should stay on the page

Actual Results

Link immediately disappears

Workaround

In the later version of Confluence (tested on Confluence 7.4.0), even disabling the com.atlassian.confluence.plugins.confluence-paste from the BANDANA database table will still have the pasted link disappear immediately.
However, the Undo (eg: CTRL+Z) function will be able to bring the disappeared link into the editor