Fix IgbTab.EnsureModulesLoaded to register parent IgbTabsModule

[Copilot]

PR #317's child-module cleanup missed IgbTab: its EnsureModulesLoaded still resolved its own IgbTabModule instead of the parent IgbTabsModule, inconsistent with the pattern applied to other child components in that effort.

Changes

• IgbTab.EnsureModulesLoaded now checks/registers IgbTabsModule (the parent) instead of IgbTabModule (its own), matching the established lazy-registration pattern used by other child components (e.g. IgbCardActions → IgbCardModule, IgbRatingSymbol → IgbRatingModule).

 protected override void EnsureModulesLoaded()
 {
-    if (!IgbTabModule.IsLoadRequested(IgBlazor))
+    if (!IgbTabsModule.IsLoadRequested(IgBlazor))
     {
-        IgbTabModule.Register(IgBlazor);
+        IgbTabsModule.Register(IgBlazor);
     }
 }

IgbTabsModule.Register already loads the underlying web module and marks the child module as requested, so routing through the parent avoids duplicate/inconsistent module resolution for a component that never renders standalone outside IgbTabs.