Restore correct Version.Details.xml Source Sha

[adamzip]

The backflow from the VMR is failing after the Source Sha in eng/Version.Details.xml was changed to an unknown value in #5789. This PR restore it back to the value it had prior to that, which was set by #5589

[Copilot]

Pull request overview

Restores the eng/Version.Details.xml <Source> SHA for the dotnet/dotnet dependency mapping back to the previously known value to unblock VMR backflow.

Changes:

• Update the dotnet/dotnet <Source> Sha to 4e6cfd9762f7562d398be31e2bff79f3e993a9c2.

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[adamzip]

@steveisok I see that this repo hasn't received a backflow in a very long time.
The most recent backflow failed because there was some wrong Sha in the Version.Details.xml file, this PR fixes it. If we merge this PR we can retrigger the subscription to get a new backflow PR opened. (CC @max-charlamb @hoyosjs )

[dkurepa]

if we do this, we have to FF afterwards, before doing a backflow. Otherwise this commit will be recognized as the last flow, and we might end up losing changes