run update-blueprint-deps to update to Ember 6.6

[mansona]

This is getting ready for the full release process. Things to note:

• I picked ember-data 5.6 because it matches what you would get in the currently released ember-cli@6.6 version
• we will be resetting the version (in a follow up PR) so that it matches the other blueprint
• the script automatically bumps all "in range" versions, I'll do a separate PR to see if there is any that need a major