Migrate to Adaptive Card 1.3 Version

[Sakthivel-Ramasamy]

Code changes commit for webexpythonsdk's Adaptive Card 1.1 to 1.3 version upgrade. Changes involve code files restructuring inline with Adaptive Card's official documentation (https://adaptivecards.io/explorer/).

[Sakthivel-Ramasamy]

set_if_not_none() function from utils.py has been removed as I did not find any usage in the entire SDK!

[Sakthivel-Ramasamy]

It is surprising. I tried the same and simulated an error to reach that particular piece of code, but it worked correctly. Can you please share the adaptive card code that you've used that led to this error?

[Joezanini]

Now I am getting a SyntaxError: f-string: expecting '}'. This is for src/webexpythonsdk/models/cards/utils.py Line 61. I think it has to do with the quotation mark placement.

[Sakthivel-Ramasamy]

Code commit for #242