feat(alb): add desync mitigation mode support @RoseSecurity (#206)
## What and WhyThis introduces support for configuring the desync mitigation mode on the AWS load balancer resource. It adds a new variable to control how the load balancer handles potentially risky HTTP desync requests, improving security configuration flexibility.
New desync mitigation mode support:
- Added the
desync_mitigation_modeargument to theaws_lbresource inmain.tf, allowing the load balancer's HTTP desync handling to be configured. - Introduced a new
desync_mitigation_modevariable invariables.tfwith validation for accepted values (monitor,defensive,strictest) and a default ofdefensive.