Exclude storybook files from unit tests and ensure 100% unit test coverage

[kgpax]

Unit test coverage has dropped from from 100% across the board to

------------------------------------|---------|----------|---------|---------|-------------------
File                                | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
------------------------------------|---------|----------|---------|---------|-------------------
All files                           |   82.12 |     96.5 |   90.62 |   80.78 |                   

This is mostly down to the .stories.tsx files being included for tests.

Adding the following lines to the collectCoverageFrom section in packages/webui/jest.config.ts will eliminate these:

'!./src/**/*.stories.{ts,tsx}',
'!**/*__mocks__*/**',

...however, coverage is still down and needs to be boosted back to 100%:

----------------------------|---------|----------|---------|---------|-------------------
File                        | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------------------------|---------|----------|---------|---------|-------------------
All files                   |   98.35 |    97.41 |   99.57 |   98.43 |