Added new courses in Eng language for c# language

[Ratheshan03]

What does this PR do?

Added new english courses with free access

For resources

Description

Added new english courses with free access for C# Programming language.
One content from youtube and other one is from Microsoft itself.

Why is this valuable (or not)?

It's free and well structured content from the C# leader (Microsoft) itself.

How do we know it's really free?

https://learn.microsoft.com/en-us/training/paths/build-dotnet-applications-csharp/
https://www.youtube.com/playlist?list=PLdo4fOcmZ0oULFjxrOagaERVAMbmG20Xe

For book lists, is it a book? For course lists, is it a course? etc.

02 new courses

Checklist:

• Read our contributing guidelines.
• Search for duplicates.
• Include author(s) and platform where appropriate.
• Put lists in alphabetical order, correct spacing.
• Add needed indications (PDF, access notes, under construction).
• Used an informative name for this pull request.

Follow-up

• Check the status of GitHub Actions and resolve any reported warnings!

[github-actions]

Linter failed, fix the error(s):

free-programming-books/courses/free-courses-en.md
366:1-380:74  warning  Alphabetical ordering: swap l.368 and l.367  alphabetize-lists  remark-lint
366:1-380:74  warning  Alphabetical ordering: swap l.372 and l.371  alphabetize-lists  remark-lint