[MAIL] Create SSL enabled tests for `SmtpClient`

[ManickaP]

Example repro case from #91377.

Follow up for #91750 which is getting only manual verification for now.

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Issue Details

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Example repro case from #91377.

Follow up for #91750 which is getting only manual verification for now.

Author:	ManickaP
Assignees:	-
Labels:	area-System.Net, untriaged, needs-area-label
Milestone:	-