fixes: U4-10413 Composition/Reorder bar gets in the way when editing or adding a property

src/Umbraco.Web.UI.Client/gulpfile.js

@@ -41,7 +41,7 @@ function processLess(files, out) {
 
     var processors = [
          autoprefixer,
-         cssnano
+         cssnano({zindex: false}),
     ];
 
     return gulp.src(files)

src/Umbraco.Web.UI.Client/src/less/components/overlays.less

@@ -2,7 +2,7 @@
     position: fixed;
     overflow: hidden;
     background: @white;
-    z-index: 996660;
+    z-index: 7500;
     animation: fadeIn 0.2s;
     box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
 }

src/Umbraco.Web.UI.Client/src/less/components/umb-lightbox.less

@@ -6,7 +6,7 @@
     left: 0;
     width: 100%;
     height: 100%;
-    z-index: 999;
+    z-index: 5000;
     display: flex;
     align-items: center;
     justify-content: center;