fix: PAB table: column selection not working on header second line (type, parameters, value)

refs #607

src/app/components/pab-table/pab-table.component.html

@@ -66,7 +66,7 @@
                 </th>
             </tr>
             <tr *ngFor="let col of columns">
-                <th *ngFor="let cell of col.cells" (click)="toggleSelection(col, $event)"
+                <th *ngFor="let cell of col.cells" (click)="toggleSelection(cell, $event)"
                     (mousedown)="preventCtrlClickBorder($event)" [class.selectable-cell]="isSelectable(cell)"
                     [class.selected-cell]="isSelected(cell)" [attr.rowspan]="rowSpan(cell)"
                     [attr.colspan]="colSpan(cell)" [title]="cellTitle(cell)">