Fix invalid_namespace_member error code description

[Copilot]

Corrects copy-paste error in invalid_namespace_member error code description that incorrectly referenced "flow setting" instead of "namespace member".

Change:

# Before
invalid_namespace_member: { description: 'The flow setting is invalid because of active model errors' }

# After  
invalid_namespace_member: { description: 'The namespace member is invalid because of active model errors' }

Addresses feedback from #670 (comment)

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[Knerio]

@copilot Recompile the docs please with bin/rake graphql:compile_docs

[Knerio]

@copilot Recompile the docs please with bin/rake graphql:compile_docs

[github-actions]

GitLab Pipeline Action

General information

Link to pipeline: https://gitlab.com/code0-tech/development/sagittarius/-/pipelines/2157716898

Status: Failed
Duration: 51 seconds

Job summaries

rubocop

669 files inspected, no offenses detected

[Knerio]

@copilot the pipeline failed