Disable all search rspec jobs with PG16 in nightly

What does this MR do and why?

Disable all search rspec jobs with PG16 in nightly

Disable them for now because we have 2k+ jobs in the nightly pipeline now, which exceeds the limit a pipeline can have.

Disable them so that we can still run the pipeline.

Fixes gitlab-org/quality/engineering-productivity/master-broken-incidents#7443 (closed)

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