Add Angstroms Length-Converter option

[DevBoiAgru]

Fixes #2175

Description of the changes:

• Adds Angstrom as a unit of length
• Angstrom can be converted to other units and vice versa

How changes were validated:

• Added unit testing

[DevBoiAgru]

@microsoft-github-policy-service agree

[DevBoiAgru]

Hi @tian-lt I hope you're doing well, just wanted to ask if this small MR could be merged? It's a small and straightforward update.

Thanks for your time! 😊

[tian-lt]

Hi @DevBoiAgru, thank you for proposing this PR. Most of the changes look good to me. However, there's a test case failure found by the pipeline.
It seems the MultipleConverterModeCalculationTest case may need some adjusts for the new unit.
Could you take a look? Let me know when you fixed it, and then I'll merge the PR if everything goes well.

[DevBoiAgru]

@tian-lt Thanks for the reply. How could I run the tests locally on my machine so that I can mention you when it's done? I think the test case should be an easy fix with the order, so I dont want to push small changes again and again until it works

Update: Nevermind i think i figured it out, i'll keep you updated

[tian-lt]

Sure. You can run those unit tests by building the unit test project locally, which is located here: https://github.com/microsoft/calculator/tree/main/src/CalculatorUnitTests
And, you may manually add a self-signed certificate to pack the unit test project to install it on your machine and then run for testing. The way to do that is exactly the same as what packing a side-load UWP app needs.
Feel free to let me know if you need helps. @DevBoiAgru

[DevBoiAgru]

@tian-lt Apologies for another mention but the most recent commit should fix the test case not passing. I have modified a test case so that it checks for the correct units. Thank you.

[tian-lt]

LGTM.
@hanzhang54 do you have any comments on this?