I was not able to override Content-Type header

[PrettySolution]

Describe the bug
I was not able to override Content-Type header as suggested in documentation for custom headers.

Technically, I should be able to override the Content-Type header by adding the key and a value in the webhook.customheaders map as the content type is also just a header but set before the custom ones.

How to reproduce it

install falco chart 4.2.4, enable falcosidekick and set up webhook connector
check logs in falco-falcosidekick Pod: Webhook - Unexpected Response (415)

set falcosidekick.enabled = true
set falcosidekick.config.webhook.address = http://xxx.yyy.194.126:10029/falco
set falcosidekick.config.webhook.method = POST
set falcosidekick.config.webhook.checkcert = false
set falcosidekick.config.webhook.customHeaders = content-type:application/json

Expected behaviour

content-type header strictly set.

• Falco version:

4.2.4

• Installation method:

Helm

[Issif]

The PR #857 fixes that issue.