feat(Layout): add flex shrink for layout side (#4752)

Author: ArgoZhang

src/BootstrapBlazor/Components/Layout/Layout.razor.scss

@@ -253,6 +253,7 @@
             width: var(--bb-layout-sidebar-width);
             transform: translateX(0);
             transition: width .3s linear;
+            flex-shrink: 0;
 
             .layout-menu {
                 border-right: 1px solid var(--bs-border-color);