DrawPanel Update: Seperating tests to test individual features

[ganimtron-10]

As we are now adding new features to the DrawPanel the current test is becoming bigger and bigger.
Due to this creating, debugging, and managing tests is becoming harder.
So to keep things simple, separating tests to validate individual parts or features of the DrawPanel.

[codecov]

Codecov Report

Merging #674 (6730308) into master (6caaa03) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #674      +/-   ##
==========================================
- Coverage   50.40%   50.38%   -0.02%     
==========================================
  Files         120      120              
  Lines       26980    27014      +34     
  Branches     2986     2988       +2     
==========================================
+ Hits        13598    13610      +12     
- Misses      12923    12945      +22     
  Partials      459      459              

Impacted Files	Coverage Δ
fury/ui/tests/test_elements.py	0.00% <0.00%> (ø)
fury/fury/ui/tests/test_elements.py	80.39% <0.00%> (-0.11%)	⬇️
fury/fury/ui/elements.py	90.11% <0.00%> (-0.07%)	⬇️

[skoudoro]

I do not see any issue. all the tests are running ok in my laptop so I am going ahead and merge this PR.

Thanks @ganimtron-10