Don't produce duplicate entries when events have non-string fields

[actgardner]

Falco emits events that include non-string fields (like proc.tty). When some outputs encountered these fields, they would re-append the previous string field because the variable was reused. This resulted in duplicated fields in the output. This PR drops the numeric fields for now and fixes the duplicated fields.

[Issif]

Hi,

I never noticed that behavior but you're right.

I tried this

curl "http://localhost:2801/" -d'{"output":"This is a test from falcosidekick","priority":"Debug","rule":"Test rule", "time":"2001-01-01T01:10:00Z","output_fields": {"proc.name":"falcosidekick","user.name":"falcosidekick", "proc.tty": 1234}}' 

And I got duplicate entries :

I discover the continue statement, I only knew break.

I'm preparing a new release, I will merge your PR and rebase on right after.

Thanks.