Analytics search event fires when exising search term is repeated

[zackkrida]

Description

Our analytics event for submitting a search fires on the /search route even when the search term is "cleared" by selecting the text in the input, deleting it, and pressing enter or the search button.

Reproduction

1. Visit https://openverse.org/ and submit a search
2. Open the developer tools of your preferred browser to the Network tavb
3. Clear the search bar, and without unfocusing the search bar, submit a search.
4. See that the event was sent.

In writing this, I remembered that it is technically impossible to clear the search bar, so this issue really happens when resubmitting the current search term, not when clearing.