Show identity overrides pagination warning

Currently, when `/api/v1/environment-document` starts serving paginated responses due to total overrides exceeding the 1MB response size limit, there's no way for the user to find out unless they notice missing overrides during local evaluation.

This will be the case for quite some time until all the server SDKs are updated to support pagination.

For now, we should check for additional pages and add a UI warning in the Environment context saying the following text:

> Environment <environment> has reached an Identity overrides in Local Evaluation mode limit. Some of the overrides will not work in Local Evaluation mode. Turn off Local Evaluation mode for the SDKs that use it or remove unneeded identity overrides.

Use the logic below to determine whether the banner should be shown: