[azsdk-cli] Support different path of "swagger_to_sdk_config.json" across SDK repos

https://github.com/Azure/azure-sdk-tools/blob/main/tools/azsdk-cli/docs/specs/6-package-updater.spec.md declares to reuse `swagger_to_sdk_config.json` and it assumes this file is in folder `eng`: https://github.com/Azure/azure-sdk-tools/blob/9c42b11a51dad2359293ebc3f7db646e0430255a/tools/azsdk-cli/Azure.Sdk.Tools.Cli/Helpers/SpecGenSdkConfigHelper.cs#L69. But actually it exists in different folder across SDK repos. There is already configuration file in rest repo to declare where `swagger_to_sdk_config.json` is (e.g. https://github.com/Azure/azure-rest-api-specs/blob/7e84a6adc29eeec1ab9e06de1a597ce7bfb7cc46/specificationRepositoryConfiguration.json#L4-L32) and you just need to read them to get the specific path for specific language repo.