Learn training: ASP.NET Core Path: Update Links on dotnet-summary.md include file

[wadepickett]

Per Dan Roth, once the ASP.NET Core Path modules are complete, update the links in the dotnet-summary.md include file to point to the relevant learning path links, and remove a few of the original links.

At repo: https://github.com/MicrosoftDocs/learn-pr
For include file:
https://github.com/MicrosoftDocs/learn-pr/blob/main/learn-pr/includes/dotnet-summary.md

Which can be found included in docs as:
(../../../includes/dotnet-summary.md)

"The number of links on this include is very high. We eventually want to encourage folks that made it to this point to choose either the ASP.NET Core frontend or backend learn paths. But first we have to build those learning paths."|

from PR discussion here:
https://github.com/MicrosoftDocs/learn-pr/pull/46920#discussion_r1786872201