Extensions: follow-up for EnC support

[jcouv]

• block edits in .NET 10
• unblock and test/implement support for EnC (this issue is referenced in source)

Relates to test plan #76130

[jaredpar]

@RikkiGibson let's use this issue to track blocking ENC for .NET 10 RTM. Once that is done file a follow up for us to start testing + enabling in the key scenarios.