fix!: Moved Company enums to a separate file (#14455)

Note: The `launch_stage` is still `BETA` for this API

https://github.com/googleapis/googleapis/blob/c4e80cd2d3321cc37cf1c3713bb02529857728d1/google/ads/admanager/v1/admanager_v1.yaml#L215

See b/405358761 where this breaking change was approved

See
googleapis/googleapis@1bc5511
and
googleapis/googleapis-gen@bb5ea2e
which includes the breaking change.

`CompanyCreditStatusEnum` exists here:

https://github.com/googleapis/google-cloud-python/blob/d0b9c9f76c9d885c17e51e866d9e68ecb3b0e6d4/packages/google-ads-admanager/google/ads/admanager_v1/types/company_enums.py#L68

`CompanyTypeEnum` exists here:

https://github.com/googleapis/google-cloud-python/blob/d0b9c9f76c9d885c17e51e866d9e68ecb3b0e6d4/packages/google-ads-admanager/google/ads/admanager_v1/types/company_enums.py#L31

Author: parthea