[DS5-8 #224] Add scenario tests for US2 US5 with regen transition update

[edykim]

• Added US2, US5 scenario tests
• Added loading screen when recipe is regenerating

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Code Coverage

Overall Project	74.21%	:green_apple:
Files changed	100%	:green_apple:

File	Coverage
Controller.java	85.44%	:green_apple: