CodeGen from PR 14554 in Azure/azure-rest-api-specs

[MFE] Discriminator definitions have "additionalProperties" (#14554)

* Enabling java client (#1)

* Revert "Enabling java client (#1)" (#2)

This reverts commit 26873d33199c64732735a5c0f92fe90f4044453e.

* discriminators have additionalProperties

* Revert "Revert "Enabling java client (#1)" (#2)"

This reverts commit 41d5801adebc54d36fba114398c84848e4b4b112.

* Revert "Enabling java client (#1)"

This reverts commit 7537c824c3620b67e18acdfe5ea650fe9c18d962.

Co-authored-by: Harneet Virk <harnvir@microsoft.com>