refactor(central-ui): drop redundant Parent Template field from Template Properties

The Template Properties card repeated the parent template, which the page
header already shows — the "inherits X" line for base templates and the
"Derived from X — composed inside Y" line for derived ones. The card now
carries only Name and Description.

src/ScadaLink.CentralUI/Components/Pages/Design/TemplateEdit.razor

@@ -323,13 +323,8 @@
                         <label class="form-label">Description</label>
                         <input type="text" class="form-control" @bind="_editDescription" />
                     </div>
-                    <div class="col-12">
-                        <label class="form-label">Parent Template</label>
-                        <input type="text" readonly class="form-control form-control-plaintext"
-                               value="@(_selectedTemplate.ParentTemplateId is int pid
-                                        ? _templates.FirstOrDefault(t => t.Id == pid)?.Name ?? $"#{pid}"
-                                        : "(none)")" />
-                    </div>
+                    @* Parent template is shown in the header above (the "inherits"
+                       / "Derived from" line), so it is not repeated here. *@
                     <div class="col-12 text-end">
                         <button class="btn btn-primary" @onclick="UpdateTemplateProperties">Save Properties</button>
                     </div>