chore(cactus-plugin-ledger-connector-corda): remove unused openapi.yaml

[aldousalvarez]

Description

After working on updating the OpenAPI extension there was one openapi.yaml on plugin-ledger-connector-corda that still has x-hyperledger-cactus. When I tried to update it manually, Peter mentioned that it should automatically update after running the generate-server script on package.json. So after further investigation I have found that this openapi.yaml is already irrelevant to the plugin-ledger-connector-corda. I have verified this since we added "documentationProvider: none" on packages/cactus-plugin-ledger-connector-corda/src/main-server/openapi-generator-config.yaml the openapi.yaml does not get updated if we run the generate-server script. As you can also see the changes on this issue #2662 one of the changes is openapi.yaml is removed from the packages/cactus-plugin-ledger-connector-corda/src/main-server/kotlin/gen/kotlin-spring/.openapi-generator/FILES since it is not being used since documentationProvider: none is now implemented.