Geo: Remove lastEventTime translation

Summary

Follow up on the feedback from @zcuddy in !72035 (comment 713293129)

I swear this translation used to do more than this 😰 This can for sure go. @nhxnguyen this will require a bit more of an intense refactor so if you'd like feel free to open a follow up issue to address this!

What needs to be done

1. Remove this translation on line 13
2. Unravel both of the <gl-sprintf /> (event and cursor)

<span v-if="lastEventTimestamp" :class="$options.classTimestamp"> <!-- $options.classTimestamp from Paul's patch above -->
  <time-ago :time="lastEventTimestamp" />
</span>

1. Remove the no longer necessary import of GlSprintf
2. Fix the breaking specs in geo_node_secondary_other_info_spec.js