fix: double scroll bar (#113)

* fix: double scroll bar

* chore: remove unused style

Author: bobbyg603

projects/ngb-filterable-dropdown/src/lib/ngb-custom-filterable-dropdown/ngb-custom-filterable-dropdown.component.scss

@@ -8,10 +8,9 @@
 }
 
 .dropdown-menu-inner {
+  z-index: 1000;
   display: flex;
   flex-direction: column;
-  max-height: 231px;
-  min-height: 76px;
   height: auto;
 }
 
@@ -66,12 +65,6 @@
   }
 }
 
-.scroll-container {
-  width: 100%;
-  min-height: 30px;
-  overflow-y: auto;
-}
-
 icon-all,
 icon-none,
 icon-checkmark {
@@ -106,9 +99,15 @@ icon-plus {
   }
 }
 
+.scroll-container {
+  width: 100%;
+  min-height: 30px;
+}
+
 .virtual-scroll-viewport {
+  display: block;
   width: 100%;
   min-width: 100%;
-  max-height: 200px;
+  height: 100%;
   min-height: 40px;
-}
+}