Test: don't refresh when waiting for pipeline

What does this MR do and why?

The affected test in this MR was failing intermittently since we were refreshing the page, which was triggering too many queries (102). This has been causing master broken incidents gitlab-org/quality/engineering-productivity/master-broken-incidents#3512 (closed)

However, we don't need to refresh the page in this test.

How to set up and validate locally

rspec ./spec/features/merge_request/user_sees_merge_request_pipelines_spec.rb

NOTE: this may fail locally because the local timeout is set to 10, whereas in CI it is set to 30 https://gitlab.com/gitlab-org/gitlab/-/blob/master/spec/support/capybara.rb?ref_type=heads#L11

MR acceptance checklist

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