[openapi-alps] Disable Rush "track changes" feature

The `openapi-alps` repo currently has the Rush "track changes" feature enabled for the projects under the `public` folder, like `public/swagger-validation-common`. I believe this was enabled because the packages under public used to be published to npmjs.com, but now they are only consumed from the unified pipeline zip. For example:

https://www.npmjs.com/package/@azure/swagger-validation-common

This "track changes" feature should probably just be disabled if we are not planning to ship these packages to npmjs.com anymore. When the feature is disabled, the files under `common/changes` should also be deleted.