Sort by similarity in Search Group's Project dropdown

What does this MR do?

Related to #332890 (closed)

This MR enables the use of order_by = similarity in the Project dropdown when a Group is selected. The Group's Project similarity sort was introduced by: !37300 (merged)

Screenshots (strongly suggested)

Taken from my gdk with some staged groups, subgroups, and projects

Before

After

Does this MR meet the acceptance criteria?

Conformity

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Security

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