Remove deprecated devfile_web_url from GraphQL API

MR: Pending

Description

We would need to remove the deprecated devfile_web_url field from GraphQL workspace_type. Pls see discussion and MR here for reference.

The field would be deprecated in GitLab release 17.8, and based on the deprecation process, https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/api/graphql/index.md#deprecation-and-removal-process. The earliest removal release would be 19.0

Acceptance Criteria

• Remove deprecated devfile_web_url field from GraphQL workspace_type
• Remove deprecated devfile_web_url method from workspace model
• Remove API doc references for this field