Remove sending email code from Jenkinsfile

[Ximinhan]

related to openshift-eng/art-tools#497

now the send umb step is a deprecated step, QE won't look at it and we didn't succeed sent it

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[vfreex]

/lgtm
Though the title could be "Remove sending email code from Jenkinsfile"

[openshift-ci]

New changes are detected. LGTM label has been removed.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[openshift-ci]

@Ximinhan: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/security	7e38788	link	false	/test security

Full PR test history. Your PR dashboard.

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