Fix Powershell Cmdlet name in How to use VM Tokens

[HarryGwinnell]

The PowerShell cmdlet is called Invoke-RestMethod, not Invoke-RestMeth as mentioned in this doc. Fix the cmdlet name so future folks who try to run these commands don't run into issues.

The command also includes a Variable reference $Resource, but uses single quotes for the string so the variable isn't being substituted. Switch to double quotes so the strings behave as expected.

Screenshot above shows the original command failing on the first line. Second line shows the command failing again, this time with an error ' The resource principal named $resource was not found'. The third line shows the command running successfully with no output, and the fourth line shows the successful token acquisition.

After this step, we're instructed to do $content = $response.Content | ConvertFrom-Json to convert the result, but attempting to do so throws an error. The following step can fetch the access token without needing to manipulate the response, so bypass this step.

[prmerger-automator]

@HarryGwinnell : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[learn-build-service-prod]

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[learn-build-service-prod]

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[v-regandowner]

@SHERMANOUKO - Can you review the proposed changes?

IMPORTANT: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged"
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