Handling invalid user input testsettings

Handling invalid user test settings values like locale and browser

Currently the exception thrown is not handled properly. This causes consuming application to encounter error.

Proposing handling this scenario like any other user input exception and gracefully.

Checklist

[x] The code change is covered by unit tests. I have added tests that prove my fix is effective or that my feature works
[x] I have performed end-to-end test locally.
[x] New and existing unit tests pass locally with my changes
[x] I have commented my code, particularly in hard-to-understand areas
[x] My changes generate no new warnings
[x] I used clear names for everything
[x] I have performed a self-review of my own code

Package	Line Rate	Branch Rate	Complexity	Health
Microsoft.PowerApps.TestEngine	91%	88%	978	✔
Summary	91% (2544 / 2789)	88% (595 / 680)	978	✔