feat(iot-hub): hide changelog section for initial releases

The IoT Hub backend sends the literal string 'Initial release' as the
changelog payload for every newly-published item. That text tells the
user nothing they don't already see from the v 1.0.0 chip in the meta
bar — just informational noise. Hide the Changelog heading + body when
the trimmed changelog equals 'Initial release'.

Both the inner section guard and the outer container guard use the new
shouldShowChangelog() helper so an item with empty readme + initial
release changelog doesn't leave an empty wrapper.

ui-ngx/src/app/modules/home/components/iot-hub/iot-hub-item-detail-dialog.component.html

@@ -294,12 +294,12 @@
     }
 
     <!-- Readme / Changelog -->
-    @if (readmeContent || item.changelog) {
+    @if (readmeContent || shouldShowChangelog()) {
       <div class="dlg-readme">
         @if (readmeContent) {
           <tb-markdown [data]="readmeContent"></tb-markdown>
         }
-        @if (item.changelog) {
+        @if (shouldShowChangelog()) {
           <h3>{{ 'iot-hub.changelog' | translate }}</h3>
           <tb-markdown [data]="item.changelog"></tb-markdown>
         }

ui-ngx/src/app/modules/home/components/iot-hub/iot-hub-item-detail-dialog.component.ts

@@ -162,7 +162,10 @@ export class TbIotHubItemDetailDialogComponent extends DialogComponent<TbIotHubI
     return this.installedItem != null;
   }
 
-
+  shouldShowChangelog(): boolean {
+    const changelog = this.item.changelog?.trim();
+    return !!changelog && changelog !== 'Initial release';
+  }
 
   hasUpdate(): boolean {
     return this.installedItem != null