Studio: When updating a dashboard SPARQL query, the columns options are not maintained

Reported by @annakristinkaufmann

**Description**
Each time the query is updated, all columns need to be reconfigured before the updated query can be saved (otherwise, the “save” button is greyed out)

**Expected behaviour**
- If the column configuration was previously set, the same configuration should be maintained upon clicking on the `Configure Columns`.
- By default (when not previously configured), all column options should be ticked: `Enable Search`, `Enable Sort`, `Enable Filter`.
- Since the column type drop-down is not doing anything at this stage, just hide it.

Start by tracing the Studio dashboard flow for updating a SPARQL query and opening Configure Columns. Check how the existing column configuration is loaded and how the save-button state is determined. Done means prior options are retained, new columns default to search, sort, and filter enabled, and the inactive column-type control is hidden.

Written by the indexing model from the issue text.