Remove th classes in job/sidebar/trigger_block.vue table

What does this MR do and why?

These classes are no longer needed and cause UI inconsistencies.

Changelog: changed

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Go to any project job page by navigating to Project > CI/CD > Jobs and select any job. For example, http://127.0.0.1:3000/gitlab-org/gitlab-test/-/jobs/127.
2. Apply this diff to force show the table in the sidebar.

diff --git a/app/assets/javascripts/jobs/components/job/sidebar/sidebar.vue b/app/assets/javascripts/jobs/components/job/sidebar/sidebar.vue
index 02c3d60557b..1f18c4f1cad 100644
--- a/app/assets/javascripts/jobs/components/job/sidebar/sidebar.vue
+++ b/app/assets/javascripts/jobs/components/job/sidebar/sidebar.vue
@@ -127,10 +127,15 @@ export default {
         />
 
         <trigger-block
-          v-if="hasTriggers"
           class="gl-py-5"
           :class="$options.borderTopClass"
-          :trigger="job.trigger"
+          :trigger="{
+            short_token: 'short token',
+            variables: [
+              { key: 'keyOne', value: 'keyOne' },
+              { key: 'keyTwo', value: 'keyTwo' }
+            ]
+          }"
         />
 
         <commit-block

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #362362