Add margin bottom

Add margin bottom for
mobile run pipeline button
on MR pipelines tab.

app/assets/javascripts/commit/pipelines/pipelines_table.vue

@@ -192,7 +192,7 @@ export default {
       <gl-button
         v-if="canRenderPipelineButton"
         block
-        class="gl-mt-3 gl-mb-0 gl-md-display-none"
+        class="gl-mt-3 gl-mb-3 gl-md-display-none"
         variant="success"
         data-testid="run_pipeline_button_mobile"
         :loading="state.isRunningMergeRequestPipeline"