app: fix broken event indexing (#5009)

## Describe your changes

We missed this on reviewing #4963 which causes a series of unfortunate
events in the data pipeline: #4999

The important diff:

```
-set_index(false)
+set_index(true)
```

## Issue ticket number and link

## Checklist before requesting a review

- [x] I have added guiding text to explain how a reviewer should test
these changes.

I have not tested this change. To test it we can run `pd` and check if
events are making it to the comet pg indexer.

- [x] If this code contains consensus-breaking changes, I have added the
"consensus-breaking" label. Otherwise, I declare my belief that there
are not consensus-breaking changes, for the following reason:

  > event indexing layer

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Co-authored-by: Conor Schaefer <[email protected]>