[ENG-10790] Dropdown section is initially too small and expands on click when filtering collection (#947)

- Ticket: https://openscience.atlassian.net/browse/ENG-10790
- Feature flag: n/a

## Summary of Changes
1. Fixed width of collection filters.

Author: nsemets

src/app/features/collections/components/collections-main-content/collections-main-content.component.html

@@ -73,11 +73,13 @@ <h3 class="highlight">{{ 'collections.searchResults.noResults' | translate }}</h
 
 <div class="flex column-gap-4 filters-resources-web">
   @if (isWeb()) {
-    @if (!isCollectionLoading()) {
-      <osf-collections-filters />
-    } @else {
-      <p-skeleton width="22rem" height="30rem" />
-    }
+    <div class="filters-column">
+      @if (!isCollectionLoading()) {
+        <osf-collections-filters />
+      } @else {
+        <p-skeleton width="22rem" height="30rem" />
+      }
+    </div>
   }
 
   <osf-collections-search-results />

src/app/features/collections/components/collections-main-content/collections-main-content.component.scss

@@ -13,3 +13,7 @@
 .card-selected {
   background: var(--bg-blue-2);
 }
+
+.filters-column {
+  flex: 0 0 22rem;
+}