Fix Azure Firewall Policy regressions. Back fix validation issues (#18233)

* Fix regressions in Firewall Policy Swagger / give firewallPolicy.json some love

* Additional lint violations

* remove breaking changes for next time. TO DO

* Revert "remove breaking changes for next time. TO DO"

This reverts commit 8f44a17.

* Reintroduce api-version for idps signature based routes. Create better names for enums to be generated in SDKs

* standardize enum names with FirewallPolicy prefix

Author: thebenwaters