Disable SendMailAsync test

[noahfalk]

This test is failing jobs in CI, see issue #72818

[ghost]

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Issue Details

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This test is failing jobs in CI, see issue #72818

Author:	noahfalk
Assignees:	-
Labels:	area-System.Net
Milestone:	-

[wfurt]

LGTM

[karelz]

I see the test failing only in 1 PR in Kusto - PR #71203 ... for period 4/1-8/4:

let failedTests = (testNameSubstring : string, methodName : string, includePR : bool, messageSubstr: string, includePassedOnRerun : bool) {
cluster('engsrvprod.kusto.windows.net').database('engineeringdata').AzureDevOpsTests
    | where TestName contains testNameSubstring
    | where includePassedOnRerun or (Outcome == 'Failed')
    | extend startOfTestName = indexof_regex(TestName, @"[^.]+$")
    | extend Method = substring(TestName, startOfTestName)
    | extend Type = substring(TestName, 0, startOfTestName - 1)
    | project-away startOfTestName
    | where (methodName == '') or (Method == methodName)
    | where Message contains messageSubstr
    | distinct JobId, WorkItemId, Message, StackTrace, Method, Type, Arguments, Outcome
    | join kind=inner (cluster('engsrvprod.kusto.windows.net').database('engineeringdata').Jobs
        | where ((Branch == 'refs/heads/main') or (Branch == 'refs/heads/master') or (includePR and (Source startswith "pr/")))
        | where Type startswith "test/functional/cli/"
            and not(Properties contains "runtime-staging")
        | summarize arg_max(Finished, Properties, Type, Branch, Source, Started, QueueName) by JobId
        | project-rename JobType = Type) on JobId
    | extend PropertiesJson = parse_json(Properties)
    | extend OS = replace_regex(tostring(PropertiesJson.operatingSystem), @'\((.*)\).*|([^\(].*)', @'\1\2')
    | extend Runtime = iif(PropertiesJson.runtimeFlavor == "mono", "Mono", iif(PropertiesJson.DefinitionName contains "coreclr", "CoreCLR", ""))
    | extend TargetBranch = extractjson("$.['System.PullRequest.TargetBranch']", Properties)
    | extend Architecture = PropertiesJson.architecture
    | extend Scenario = iif(isempty(PropertiesJson.scenario), "--", PropertiesJson.scenario)
    //| extend DefinitionName = PropertiesJson.DefinitionName
    | project-away PropertiesJson
};
failedTests('', 'SendMailAsync_CanBeCanceled_CancellationToken', true, '', true);

[karelz]

Ah, never mind. The report is on Hang -- that would not show up in Kusto.