Fix parallel job dropwdown cutoff

By adding a min-height to the pipeline graph
container equivalent to the dropdown height,
we are 100% certain that we will always have
enough space to show the job dropdown.

app/assets/stylesheets/pages/pipelines.scss

@@ -445,6 +445,7 @@
 .pipeline-tab-content {
   display: flex;
   width: 100%;
+  min-height: $dropdown-max-height-lg;
   background-color: $gray-light;
   padding: $gl-padding 0;
   overflow: auto;

changelogs/unreleased/231348-fix-parallel-jobs-dropdown-from-cutting-off-in-the-pipeline-graph.yml

+---
+title: Fix parallel jobs dropdown from cutting off in small pipeline graphs
+merge_request: 39108
+author:
+type: fixed