Remove google_gke_hub_feature_membership auto upgrades content

[rileykarson]

This appears to have been removed from docs.cloud.google.com, and the link to the content was on devsite.

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[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 1 file changed, 48 deletions(-))
google-beta provider: Diff ( 1 file changed, 48 deletions(-))

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 1 file changed, 2 insertions(+), 51 deletions(-))
google-beta provider: Diff ( 1 file changed, 2 insertions(+), 51 deletions(-))