Provide option to run reload POST call in insecure mode when tls is enabled on app endpoint

[gmhegde86]

I am using config reloader to reload alertmanager app on a configmap change, the endpoint has https with mtls enabled, however the config-reloader fails to reload with the following error:

2024/10/23 04:26:10 Watching directory: "/etc/alertmanager/config"
2024/10/23 04:26:10 Watching directory: "/etc/alertmanager/tls_assets"
2024/10/23 04:27:27 config map updated
2024/10/23 04:27:32 error: Post https://localhost:9093/-/reload: x509: certificate signed by unknown authority
2024/10/23 04:27:32 config map updated
2024/10/23 04:27:32 error: Post https://localhost:9093/-/reload: x509: certificate signed by unknown authority

The certificate used is root ca cert of our organization. When we looked into this error, a workaround suggested is to run the POST call with insecure mode (-k curl option/insecureSkipVerify=True for apps), however there doesn't isn't any configurable option to run the reload post call in insecure mode