Add default_enabled param to sidebar_refactor feature flag

What does this MR do?

There have been several MRs by different people related to &5647 (closed), using the feature sidebar_refactor. Nevertheless, some of them use the default_enabled param and others don't.

In this MR we align them by adding the param to all of them.

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.