ui: fix columns selector being cut

Previously, when the number of rows on the Jobs table was smaller
than 3, the height of the area was not enough to show the
columns selector, making it get cut and not displayed the "Apply"
button unless you scrolled.
This commit adds a min-height for that area, making sure the
column selector will be displayed completely.

Fixes #104619

Release note (bug fix): The column selector on the Jobs page
is no longer getting cut.

pkg/ui/workspaces/cluster-ui/src/jobs/jobs.module.scss

@@ -255,4 +255,5 @@
 .table-area {
   position: relative;
   overflow-x: scroll;
+  min-height: 450px;
 }